README.md

@@ -344,6 +344,9 @@ Then put it behind your existing reverse proxy like everything else
       action — resolved server-side (one atomic operation, not one
       request per track) the same way launching a playlist already
       expands into everything it contains — see docs/architecture.md
+- [x] Installable as a PWA (manifest + icons, standalone display,
+      no service worker — this app has nothing worth caching offline)
+      — see docs/architecture.md
 - [ ] Try a full party end-to-end with two real accounts (still the main gap)
 - [ ] Try casting to a real Chromecast (only the SDK's own bootstrap is
       confirmed here — no real device/session)

client/build.mjs

@@ -11,7 +11,7 @@
 //   npm run watch   -> rebuilds on save, for local dev (see README's
 //                      Running locally section)
 import * as esbuild from 'esbuild';
-import { copyFileSync, mkdirSync } from 'fs';
+import { copyFileSync, cpSync, mkdirSync } from 'fs';
 import path from 'path';
 import { fileURLToPath } from 'url';
 
@@ -20,6 +20,11 @@ const outdir = path.join(here, 'dist');
 
 mkdirSync(outdir, { recursive: true });
 copyFileSync(path.join(here, 'src', 'index.html'), path.join(outdir, 'index.html'));
+// PWA manifest + icons (manifest.webmanifest, icons/*) - see
+// docs/architecture.md's "Progressive Web App" section. Copied wholesale
+// rather than named file-by-file like index.html above, so adding another
+// icon later needs no build.mjs change.
+cpSync(path.join(here, 'src', 'public'), outdir, { recursive: true });
 
 const buildOptions = {
   entryPoints: [path.join(here, 'src', 'app.ts')],

client/src/index.html

@@ -4,6 +4,24 @@
   <meta charset="utf-8" />
   <meta name="viewport" content="width=device-width, initial-scale=1" />
   <title>Watch Party</title>
+
+  <!-- PWA - see docs/architecture.md's "Progressive Web App" section.
+       theme-color/background_color both come straight from base.css's
+       --bg-header/--bg (the manifest can't read CSS custom properties,
+       so these are duplicated by hand - if that palette ever changes,
+       update manifest.webmanifest to match). -->
+  <link rel="manifest" href="manifest.webmanifest" />
+  <meta name="theme-color" content="#221d24" />
+  <link rel="icon" type="image/png" href="icons/favicon.png" />
+
+  <!-- iOS ignores the manifest above for installed-app chrome - Safari
+       needs its own separate meta tags/link for the equivalent
+       standalone/home-screen-icon behavior. -->
+  <link rel="apple-touch-icon" href="icons/apple-touch-icon.png" />
+  <meta name="apple-mobile-web-app-capable" content="yes" />
+  <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent" />
+  <meta name="apple-mobile-web-app-title" content="Watch Party" />
+
   <link rel="stylesheet" href="app.css" />
   <script src="https://cdnjs.cloudflare.com/ajax/libs/hls.js/1.5.17/hls.min.js"></script>
   <script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/4.7.5/socket.io.min.js"></script>

client/src/public/manifest.webmanifest

@@ -0,0 +1,16 @@
+{
+  "name": "Watch Party",
+  "short_name": "Watch Party",
+  "description": "Regardez et écoutez en même temps que les autres utilisateurs de votre serveur Emby.",
+  "lang": "fr",
+  "start_url": "/",
+  "display": "standalone",
+  "background_color": "#151216",
+  "theme_color": "#221d24",
+  "categories": ["entertainment", "multimedia"],
+  "icons": [
+    { "src": "icons/icon-192.png", "sizes": "192x192", "type": "image/png", "purpose": "any" },
+    { "src": "icons/icon-512.png", "sizes": "512x512", "type": "image/png", "purpose": "any" },
+    { "src": "icons/icon-512-maskable.png", "sizes": "512x512", "type": "image/png", "purpose": "maskable" }
+  ]
+}

docs/architecture.md

@@ -3419,6 +3419,87 @@ tokens) rather than eyeballed. **Not verified**: an actual large
 discography queuing correctly end to end against a real server - no
 Emby login reachable from this sandbox.
 
+## Progressive Web App
+
+Asked for directly, as a follow-up to Picture-in-picture above: since
+that feature's automatic-on-backgrounding variant turned out not to be
+achievable (browsers require a *fresh* user gesture for
+`requestPictureInPicture()` - confirmed empirically, not just from
+docs, by calling it from a real `visibilitychange` listener in a real
+Chromium tab and getting `NotAllowedError` even with
+`navigator.userActivation.hasBeenActive === true` from an earlier real
+click), a PWA install was asked for instead. **Worth being explicit
+about, since it'd be easy to assume otherwise**: installing this app
+does not change that outcome - the transient-activation requirement is
+part of the Picture-in-Picture spec itself, not something tied to
+being loaded in a browser tab versus an installed, `display: standalone`
+window. The one Chrome feature that skips that requirement
+(media-session-handler-based automatic PiP) stays desktop-only and
+getUserMedia-gated regardless of install state, and nothing above
+touches that gate. So the manual `#pipBtn` toggle remains the way to
+enter PiP either way - a PWA install is its own, independently useful
+feature here (an icon on the home screen, no browser chrome/URL bar
+around the player, an OS-level app-switcher entry), not a workaround
+for the previous section's limitation.
+
+Three pieces, all standard and Chromium/Android-focused since that's
+this app's stated mobile target (see Picture-in-picture above):
+
+- **`client/src/public/manifest.webmanifest`** - `name`/`short_name`,
+  `display: "standalone"`, and `background_color`/`theme_color` copied
+  by hand from `base.css`'s `--bg`/`--bg-header` (a manifest can't read
+  CSS custom properties, so these two are duplicated on purpose - if
+  that palette ever changes, update both places). `start_url: "/"`,
+  `lang: "fr"` matching `index.html`'s own `<html lang="fr">`. No
+  `service worker` - confirmed against MDN's own installability
+  requirements that Chrome does not require one for the install
+  prompt, and this app has no real use for one: every page is either
+  live party/socket state or a proxied Emby catalog, and caching either
+  offline would mean showing stale library data or a stale party that's
+  already gone, not a working offline mode - so skipping it avoids a
+  whole stale-cache-invalidation problem this app doesn't need to
+  solve.
+- **Icons** - hand-authored SVG (this project has no existing
+  logo/brand asset), rasterized to PNG at the sizes each consumer
+  needs (192/512 for the manifest, 180 for `apple-touch-icon`, 32 for
+  the browser-tab favicon) via a `<canvas>` in a real browser rather
+  than an image-editing tool, since that's what was available here.
+  Two source SVGs, not one: `icon.svg` fills the canvas (used for the
+  manifest's `"any"` purpose, the favicon, and `apple-touch-icon` -
+  none of those get OS-mask-cropped) and `icon-maskable.svg` scales
+  the same design down (~75%) so its farthest content point sits
+  inside Android's adaptive-icon safe zone (a circle of ~30.5% of the
+  icon's radius from center) - checked by computing the actual
+  farthest-point distance for both versions, not just eyeballed,
+  since a maskable icon that ignores that zone gets silently clipped
+  by circular-mask launchers.
+- **`index.html`** - `<link rel="manifest">`, a `theme-color` meta
+  (Chrome/Android chrome), and the separate iOS-only tags Safari needs
+  instead of reading the manifest for the equivalent behavior
+  (`apple-touch-icon` link, `apple-mobile-web-app-capable`,
+  `apple-mobile-web-app-status-bar-style`, `apple-mobile-web-app-title`).
+
+`build.mjs` gained one `cpSync(src/public, dist, { recursive: true })`
+call alongside its existing `index.html` copy, rather than naming the
+manifest and every icon individually - adding another icon later needs
+no build.mjs change. `express.static` (already serving all of
+`client/dist` unconditionally) picks up `manifest.webmanifest` and
+`icons/*` with no server-side change at all.
+
+Verified: full `typecheck`/`build` (client only). Confirmed directly
+against a real running instance of this server, not just assumed:
+`manifest.webmanifest` and all three manifest icons resolve `200` with
+the correct `application/manifest+json`/`image/png` content types
+(express's static middleware infers both from the file extension
+correctly on its own), the `apple-touch-icon` link resolves `200`, the
+generated PNGs are genuinely the declared dimensions (32/180/192/512),
+and the page's own console shows no manifest-related warnings after
+loading it. **Not verified**: an actual "Add to Home Screen"/install
+prompt, or the installed app's standalone window, on a real device -
+no device reachable from this sandbox, same standing gap as every
+other browser-native integration in this project (casting, PiP, the
+intro-skip buttons).
+
 ## Known limitations
 
 - Playback always goes through `hls.js` against whatever Emby's