Add a favicon, home-screen icons and a web manifest

The favicon is a bowl of soup: this household's catalog is half keitto, so it
is at least honest. favicon.svg follows the system theme in the tab strip.

Home-screen icons cannot do the same. They must be opaque and must not change
with the theme, so assets/icon.svg is a separate fixed-colour source, with the
artwork inside the central 80% for Android to mask to any launcher shape. The
same 512 is declared maskable in the manifest.

`make icons` rasterises with rsvg-convert and compresses with
`oxipng -o max --zopfli`, which beat `optipng -o7` at every size — 5860 bytes
against 6109 for the three files. Plain `oxipng -o max` was not an upgrade: it
won the two small icons and lost the 512, ending up larger overall. All output
verified pixel-identical to the rasterizer. The PNGs are committed so the
build needs no rasterizer.

Two things that only fail on a real device, so both are covered by smoke
checks: Go has no mime entry for .webmanifest and served it as octet-stream,
which browsers ignore; and a manifest fetch carries no credentials by default,
so behind Basic auth it needs crossorigin="use-credentials" or it 401s.

Makefile

@@ -3,6 +3,7 @@
 COMPOSE ?= podman compose
 BIN     := foodster
 PKG     := ./cmd/foodster
+STATIC  := cmd/foodster/static
 
 # Vendored Datastar client. Bump, run `make vendor`, commit the result.
 DATASTAR_VERSION ?= v1.0.3
@@ -18,7 +19,7 @@ endif
 GOFILES = $(shell find . -name '*.go' -not -name '*_templ.go' 2>/dev/null)
 
 .DEFAULT_GOAL := help
-.PHONY: help generate build run seed test smoke check lint fix vendor image push release up down logs clean
+.PHONY: help generate build run seed test smoke check lint fix icons vendor image push release up down logs clean
 
 help: ## Show this help
 	@grep -hE '^[a-zA-Z_-]+:.*## ' $(MAKEFILE_LIST) \
@@ -51,10 +52,20 @@ check: ## Everything that must pass before a commit
 	@$(MAKE) --no-print-directory smoke
 	@echo "check: all passed"
 
+icons: ## Rasterise home-screen PNGs from assets/icon.svg and optimise them
+	rsvg-convert -w 180 -h 180 assets/icon.svg -o $(STATIC)/apple-touch-icon.png
+	rsvg-convert -w 192 -h 192 assets/icon.svg -o $(STATIC)/icon-192.png
+	rsvg-convert -w 512 -h 512 assets/icon.svg -o $(STATIC)/icon-512.png
+	# oxipng -o max alone loses to optipng on the 512; --zopfli wins at every
+	# size. Slow, but these are three tiny files built by hand.
+	oxipng -o max --zopfli --quiet \
+		$(STATIC)/apple-touch-icon.png $(STATIC)/icon-192.png $(STATIC)/icon-512.png
+	@ls -l $(STATIC)/*.png
+
 vendor: ## Re-download the Datastar client (DATASTAR_VERSION=v1.0.3)
-	curl -sSfL -o cmd/foodster/static/datastar.js \
+	curl -sSfL -o $(STATIC)/datastar.js \
 		"https://cdn.jsdelivr.net/gh/starfederation/datastar@$(DATASTAR_VERSION)/bundles/datastar.js"
-	@head -1 cmd/foodster/static/datastar.js
+	@head -1 $(STATIC)/datastar.js
 
 lint: generate ## go vet, gofmt check, golangci-lint when installed
 	go vet ./...

README.md

@@ -27,8 +27,12 @@ Working:
 
 Still to build:
 
+- **UI polish.** Checkbox chips hide the native control and signal state only
+  through background colour, so "Tarjoillaan lisukkeiden kanssa" gives no
+  clear read of on versus off. Show a real checkbox. Same applies to the
+  category and side chips.
 - Light / dark theme switch, saved per device (PRD §7.4).
-- A proper app header and a `favicon.svg`.
+- A proper app header.
 - Stage 2: the seven-meal suggester, which starts once there is history to
   weight against.
 
@@ -102,6 +106,21 @@ a scratch database:
 make seed                      # or: SEED=seeds/other.json make seed
 ```
 
+## Icons
+
+`cmd/foodster/static/favicon.svg` is the browser-tab icon and follows the
+system theme. The home-screen icons are PNGs, because a home-screen icon
+cannot be transparent and must not change with the theme; they are rasterised
+from `assets/icon.svg`, which is opaque and keeps the artwork inside the
+central 80% so Android can mask it to any shape.
+
+```sh
+make icons      # rsvg-convert, then optipng -o7
+```
+
+The PNGs are committed so the build needs no rasterizer. Re-run `make icons`
+after editing `assets/icon.svg`.
+
 ## Migrations
 
 Numbered SQL files in `cmd/foodster/migrations`, embedded in the binary and

assets/icon.svg

@@ -0,0 +1,19 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" width="512" height="512"
+     role="img" aria-label="Foodster">
+  <!-- Source for the home-screen PNGs; `make icons` rasterises it.
+       Unlike favicon.svg this one is opaque and fixed-colour: a home screen
+       icon cannot be transparent and must not change with the system theme.
+       The bowl sits inside the central 80% so Android can mask it to any
+       shape without clipping the artwork. -->
+  <rect width="512" height="512" fill="#15616D"/>
+  <g transform="translate(112 112) scale(9)">
+    <g fill="#ECEDE8">
+      <rect x="1.5" y="12" width="29" height="3.2" rx="1.6"/>
+      <path d="M3.5 15.2 h25 a12.5 12.5 0 0 1 -25 0 z"/>
+    </g>
+    <g fill="none" stroke="#ECEDE8" stroke-width="3" stroke-linecap="round">
+      <path d="M11.5 9 c0 -2.1 2.1 -2.6 2.1 -4.6"/>
+      <path d="M19 9 c0 -2.1 2.1 -2.6 2.1 -4.6"/>
+    </g>
+  </g>
+</svg>

cmd/foodster/main.go

@@ -15,6 +15,7 @@ import (
 	"flag"
 	"fmt"
 	"log"
+	"mime"
 	"net/http"
 	"os"
 	"os/signal"
@@ -140,6 +141,10 @@ func openDB(path string) (*sql.DB, error) {
 }
 
 func routes(db *sql.DB, loc *time.Location, password string) http.Handler {
+	// Go's mime table has no entry for .webmanifest, and a manifest served as
+	// octet-stream is ignored by the browser.
+	_ = mime.AddExtensionType(".webmanifest", "application/manifest+json")
+
 	a := &app{db: db, loc: loc}
 
 	mux := http.NewServeMux()

cmd/foodster/static/favicon.svg

@@ -0,0 +1,16 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32" role="img" aria-label="Foodster">
+  <!-- Kulho: a bowl with steam. Finnish dinner is soup more often than not,
+       and this household's own catalog is half keitto. -->
+  <style>
+    svg { color: #15616D; }
+    @media (prefers-color-scheme: dark) { svg { color: #58C6D2; } }
+  </style>
+  <g fill="currentColor">
+    <rect x="1.5" y="12" width="29" height="3.2" rx="1.6"/>
+    <path d="M3.5 15.2 h25 a12.5 12.5 0 0 1 -25 0 z"/>
+  </g>
+  <g fill="none" stroke="currentColor" stroke-width="3" stroke-linecap="round">
+    <path d="M11.5 9 c0 -2.1 2.1 -2.6 2.1 -4.6"/>
+    <path d="M19 9 c0 -2.1 2.1 -2.6 2.1 -4.6"/>
+  </g>
+</svg>

cmd/foodster/static/manifest.webmanifest

@@ -0,0 +1,17 @@
+{
+  "id": "/",
+  "name": "Foodster",
+  "short_name": "Foodster",
+  "lang": "fi",
+  "dir": "ltr",
+  "start_url": "/",
+  "scope": "/",
+  "display": "standalone",
+  "background_color": "#ECEDE8",
+  "theme_color": "#15616D",
+  "icons": [
+    { "src": "/static/icon-192.png", "sizes": "192x192", "type": "image/png" },
+    { "src": "/static/icon-512.png", "sizes": "512x512", "type": "image/png" },
+    { "src": "/static/icon-512.png", "sizes": "512x512", "type": "image/png", "purpose": "maskable" }
+  ]
+}

cmd/foodster/views.templ

@@ -76,7 +76,14 @@ templ page(title, current string) {
 			<meta charset="utf-8"/>
 			<meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover"/>
 			<meta name="color-scheme" content="light dark"/>
+			<meta name="theme-color" media="(prefers-color-scheme: light)" content="#ECEDE8"/>
+			<meta name="theme-color" media="(prefers-color-scheme: dark)" content="#121316"/>
 			<title>{ title }</title>
+			<link rel="icon" href="/static/favicon.svg" type="image/svg+xml"/>
+			<link rel="apple-touch-icon" href="/static/apple-touch-icon.png"/>
+			<!-- use-credentials: the manifest is fetched behind Basic auth and
+			     would otherwise come back 401 and be ignored. -->
+			<link rel="manifest" href="/static/manifest.webmanifest" crossorigin="use-credentials"/>
 			<link rel="stylesheet" href="/static/app.css"/>
 			<script type="module" src="/static/datastar.js"></script>
 		</head>

mockups/favicon/a-kulho.svg

@@ -0,0 +1,16 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32" role="img" aria-label="Foodster">
+  <!-- Kulho: a bowl with steam. Finnish dinner is soup more often than not,
+       and this household's own catalog is half keitto. -->
+  <style>
+    svg { color: #15616D; }
+    @media (prefers-color-scheme: dark) { svg { color: #58C6D2; } }
+  </style>
+  <g fill="currentColor">
+    <rect x="1.5" y="12" width="29" height="3.2" rx="1.6"/>
+    <path d="M3.5 15.2 h25 a12.5 12.5 0 0 1 -25 0 z"/>
+  </g>
+  <g fill="none" stroke="currentColor" stroke-width="3" stroke-linecap="round">
+    <path d="M11.5 9 c0 -2.1 2.1 -2.6 2.1 -4.6"/>
+    <path d="M19 9 c0 -2.1 2.1 -2.6 2.1 -4.6"/>
+  </g>
+</svg>

mockups/favicon/b-kattila.svg

@@ -0,0 +1,14 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32" role="img" aria-label="Foodster">
+  <!-- Kattila: a cooking pot, lid on, handles out. Cooking rather than eating. -->
+  <style>
+    svg { color: #15616D; }
+    @media (prefers-color-scheme: dark) { svg { color: #58C6D2; } }
+  </style>
+  <g fill="currentColor">
+    <circle cx="16" cy="6" r="2.5"/>
+    <rect x="2" y="9" width="28" height="3.4" rx="1.7"/>
+    <rect x="0" y="14" width="5.5" height="3.2" rx="1.6"/>
+    <rect x="26.5" y="14" width="5.5" height="3.2" rx="1.6"/>
+    <path d="M5 13.6 h22 v6.9 a5.5 5.5 0 0 1 -5.5 5.5 h-11 a5.5 5.5 0 0 1 -5.5 -5.5 z"/>
+  </g>
+</svg>

mockups/favicon/c-lusikka.svg

@@ -0,0 +1,12 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32" role="img" aria-label="Foodster">
+  <!-- Lusikka: one spoon, set on the diagonal. A fork is the cliché; a spoon
+       on its own is not, and it stays a single solid shape at any size. -->
+  <style>
+    svg { color: #15616D; }
+    @media (prefers-color-scheme: dark) { svg { color: #58C6D2; } }
+  </style>
+  <g fill="currentColor" transform="rotate(34 16 16)">
+    <ellipse cx="16" cy="9.5" rx="5.4" ry="7"/>
+    <rect x="13.9" y="15" width="4.2" height="14" rx="2.1"/>
+  </g>
+</svg>

mockups/favicon/d-ruisleipa.svg

@@ -0,0 +1,14 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 32" role="img" aria-label="Foodster">
+  <!-- Ruisleipä: the Finnish rye loaf, hole in the middle. Nothing else in a
+       tab strip looks like this — which is the point, and also the risk. -->
+  <style>
+    .hole { fill: #ECEDE8; }
+    .loaf { fill: #6B4636; }
+    @media (prefers-color-scheme: dark) {
+      .hole { fill: #121316; }
+      .loaf { fill: #9A6E52; }
+    }
+  </style>
+  <circle class="loaf" cx="16" cy="16" r="14"/>
+  <circle class="hole" cx="16" cy="16" r="3.8"/>
+</svg>

mockups/favicon/index.html

@@ -0,0 +1,118 @@
+<!doctype html>
+<html lang="en" data-theme="auto">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<title>Foodster — favicon options</title>
+<link rel="icon" href="a-kulho.svg" type="image/svg+xml">
+<style>
+:root{
+  color-scheme: light dark;
+  --paper: light-dark(#ECEDE8, #121316);
+  --card:  light-dark(#FFFFFF, #1C1E22);
+  --ink:   light-dark(#14161A, #E9EAE5);
+  --muted: light-dark(#6B6F6A, #8B8F89);
+  --line:  light-dark(#D5D6D0, #2C2F34);
+}
+html[data-theme="light"]{color-scheme:only light;}
+html[data-theme="dark"] {color-scheme:only dark;}
+*{box-sizing:border-box;}
+body{margin:0;background:var(--paper);color:var(--ink);
+  font-family:system-ui,sans-serif;font-size:16px;line-height:1.45;}
+.wrap{max-width:900px;margin:0 auto;padding:24px 20px 60px;}
+h1{font-size:20px;letter-spacing:-.02em;margin:0 0 4px;}
+.lede{margin:0 0 22px;color:var(--muted);font-size:14px;}
+.themebtn{font:inherit;font-size:13px;background:var(--card);border:1px solid var(--line);
+  color:var(--muted);padding:7px 12px;border-radius:7px;cursor:pointer;margin-bottom:22px;}
+
+.opt{background:var(--card);border:1px solid var(--line);border-radius:12px;
+  padding:18px;margin-bottom:14px;}
+.opt h2{font-size:16px;margin:0 0 2px;letter-spacing:-.02em;}
+.opt p{margin:0 0 14px;font-size:13.5px;color:var(--muted);}
+.sizes{display:flex;align-items:flex-end;gap:22px;flex-wrap:wrap;}
+.size{text-align:center;}
+.size img{display:block;}
+.size span{display:block;margin-top:6px;font-size:10px;letter-spacing:.06em;
+  text-transform:uppercase;color:var(--muted);}
+
+/* A browser tab is the real test: 16px against the tab strip. */
+.tabsim{margin-top:16px;display:flex;gap:10px;flex-wrap:wrap;}
+.tab{display:flex;align-items:center;gap:7px;border-radius:8px 8px 0 0;
+  padding:7px 14px 7px 10px;font-size:12.5px;}
+.tab img{width:16px;height:16px;}
+.onwhite{background:#fff;color:#333;border:1px solid #ddd;}
+.ondark{background:#1b1d22;color:#bbb;border:1px solid #33363c;}
+</style>
+</head>
+<body>
+<div class="wrap">
+  <h1>Foodster — favicon, round two</h1>
+  <p class="lede">Objects from the kitchen rather than geometry. The 16&nbsp;px row and the tab strips are the only test that counts.</p>
+  <button class="themebtn" id="t">Theme: auto</button>
+
+  <div class="opt">
+    <h2>A · Kulho</h2>
+    <p>A bowl with steam. This household's catalog is half <em>keitto</em>, so soup is honest branding.</p>
+    <div class="sizes">
+      <div class="size"><img src="a-kulho.svg" width="16" height="16"><span>16</span></div>
+      <div class="size"><img src="a-kulho.svg" width="32" height="32"><span>32</span></div>
+      <div class="size"><img src="a-kulho.svg" width="64" height="64"><span>64</span></div>
+      <div class="size"><img src="a-kulho.svg" width="180" height="180"><span>180</span></div>
+    </div>
+    <div class="tabsim">
+      <span class="tab onwhite"><img src="a-kulho.svg" alt="">Foodster</span>
+      <span class="tab ondark"><img src="a-kulho.svg" alt="">Foodster</span>
+    </div>
+  </div>
+
+  <div class="opt">
+    <h2>B · Kattila</h2>
+    <p>A pot with the lid on and handles out. About cooking rather than eating.</p>
+    <div class="sizes">
+      <div class="size"><img src="b-kattila.svg" width="16" height="16"><span>16</span></div>
+      <div class="size"><img src="b-kattila.svg" width="32" height="32"><span>32</span></div>
+      <div class="size"><img src="b-kattila.svg" width="64" height="64"><span>64</span></div>
+      <div class="size"><img src="b-kattila.svg" width="180" height="180"><span>180</span></div>
+    </div>
+    <div class="tabsim">
+      <span class="tab onwhite"><img src="b-kattila.svg" alt="">Foodster</span>
+      <span class="tab ondark"><img src="b-kattila.svg" alt="">Foodster</span>
+    </div>
+  </div>
+
+  <div class="opt">
+    <h2>C · Lusikka</h2>
+    <p>One spoon on the diagonal. A fork is the cliché; a lone spoon is not, and it stays one solid shape at any size.</p>
+    <div class="sizes">
+      <div class="size"><img src="c-lusikka.svg" width="16" height="16"><span>16</span></div>
+      <div class="size"><img src="c-lusikka.svg" width="32" height="32"><span>32</span></div>
+      <div class="size"><img src="c-lusikka.svg" width="64" height="64"><span>64</span></div>
+      <div class="size"><img src="c-lusikka.svg" width="180" height="180"><span>180</span></div>
+    </div>
+    <div class="tabsim">
+      <span class="tab onwhite"><img src="c-lusikka.svg" alt="">Foodster</span>
+      <span class="tab ondark"><img src="c-lusikka.svg" alt="">Foodster</span>
+    </div>
+  </div>
+
+  <div class="opt">
+    <h2>D · Ruisleipä</h2>
+    <p>The rye loaf with its hole. Nothing else in a tab strip looks like this — which is the appeal and also the risk of reading as a ring.</p>
+    <div class="sizes">
+      <div class="size"><img src="d-ruisleipa.svg" width="16" height="16"><span>16</span></div>
+      <div class="size"><img src="d-ruisleipa.svg" width="32" height="32"><span>32</span></div>
+      <div class="size"><img src="d-ruisleipa.svg" width="64" height="64"><span>64</span></div>
+      <div class="size"><img src="d-ruisleipa.svg" width="180" height="180"><span>180</span></div>
+    </div>
+    <div class="tabsim">
+      <span class="tab onwhite"><img src="d-ruisleipa.svg" alt="">Foodster</span>
+      <span class="tab ondark"><img src="d-ruisleipa.svg" alt="">Foodster</span>
+    </div>
+  </div>
+</div>
+<script>
+const h=document.documentElement,b=document.getElementById('t'),m=['auto','light','dark'];
+b.onclick=()=>{const n=m[(m.indexOf(h.dataset.theme)+1)%3];h.dataset.theme=n;b.textContent='Theme: '+n;};
+</script>
+</body>
+</html>

scripts/smoke.sh

@@ -54,6 +54,17 @@ check "healthz needs no password" \
 check "datastar client is served" \
 	"$(curl -s -o /dev/null -w '%{http_code}' -u ":$pass" "http://$addr/static/datastar.js")" "200"
 
+check "favicon is served" \
+	"$(curl -s -o /dev/null -w '%{http_code}' -u ":$pass" "http://$addr/static/favicon.svg")" "200"
+
+check "apple touch icon is served" \
+	"$(curl -s -o /dev/null -w '%{http_code}' -u ":$pass" "http://$addr/static/apple-touch-icon.png")" "200"
+
+# A manifest served as octet-stream is silently ignored by the browser.
+check "manifest has the right content type" \
+	"$(curl -s -o /dev/null -w '%{content_type}' -u ":$pass" "http://$addr/static/manifest.webmanifest")" \
+	"application/manifest+json"
+
 check "catalog starts empty" \
 	"$(curl -s -u ":$pass" "http://$addr/ruoat")" "0 pääruokaa"