Add "Mein Zimmer" room-control page (Home Assistant, proxied through the backend)

Implements the room-control page from the design mockup: a scenes row above cards
for shutters, color lamps, and brightness-only lamps, all driven by a new
`general.ha` config section (server URL, token, ordered device/scene lists).

The backend proxies every Home Assistant call server-side (GET/POST /api/ha/...)
rather than the browser calling Home Assistant directly, so the long-lived token
never leaves the LAN device and Home Assistant's own CORS settings don't need to
know about musicmouse at all. Card kind (shutter/color/brightness-only) is
inferred at runtime from what Home Assistant reports about each entity, not
configured explicitly.

Also stops tracking python-backend/config.yml, which had drifted into the repo
despite its own header saying it shouldn't be - it now carries real credentials
locally and needs to stay untracked.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/lib/keyboard.ts

@@ -10,15 +10,16 @@ playing), and seeking is the one thing a real player can do that the mockup coul
 */
 
 import type { Album } from "../api/types";
-import type { Filter, Mode, Results } from "./search";
+import type { Group, Mode, Results } from "./search";
 
 export interface UiState {
   search: string;
   mode: Mode;
-  filter: Filter;
+  /** `null` is the bare root screen (three shelves); otherwise which one is open. */
+  group: Group | null;
   category: string | null;
   selIndex: number;
-  view: "browse" | "play";
+  view: "browse" | "play" | "room";
   openAlbumId: string | null;
   showHelp: boolean;
   cols: number;
@@ -27,7 +28,7 @@ export interface UiState {
 export const initialUiState: UiState = {
   search: "",
   mode: "albums",
-  filter: "all",
+  group: null,
   category: null,
   selIndex: 0,
   view: "browse",
@@ -49,7 +50,7 @@ export type Action =
 /** Matches the mockup's `/^[a-zA-Z0-9]$/`, widened to the umlauts a German title needs. */
 const SEARCHABLE = /^[\p{L}\p{N}]$/u;
 
-const FILTER_ORDER: Filter[] = ["all", "music", "book"];
+const GROUP_ORDER: Group[] = ["music", "audiobooks", "podcasts"];
 
 export const VOLUME_STEP = 10;
 export const SEEK_STEP = 15;
@@ -91,9 +92,18 @@ function escape(state: UiState): Action[] {
   if (state.showHelp || state.openAlbumId !== null) {
     return [{ type: "ui", patch: { showHelp: false, openAlbumId: null } }];
   }
+  if (state.view === "play" || state.view === "room") {
+    return [{ type: "ui", patch: { view: "browse" } }];
+  }
   if (state.search) return [{ type: "ui", patch: { search: "", selIndex: 0 } }];
   if (state.mode === "tracks") return [{ type: "ui", patch: { mode: "albums", selIndex: 0 } }];
-  return [{ type: "ui", patch: { category: null, selIndex: 0 } }];
+  if (state.category !== null) return [{ type: "ui", patch: { category: null, selIndex: 0 } }];
+  return [{ type: "ui", patch: { group: null, selIndex: 0 } }];
+}
+
+/** The true root: nothing chosen yet, rendered as three shelves rather than a list. */
+function isRootShelf(state: UiState): boolean {
+  return state.group === null && !state.search && state.mode === "albums" && state.category === null;
 }
 
 export interface KeyEvent {
@@ -129,10 +139,11 @@ export function handleKey(event: KeyEvent, state: UiState, results: Results): Ac
 
   switch (key) {
     case "Tab": {
-      const next = FILTER_ORDER[(FILTER_ORDER.indexOf(state.filter) + 1) % FILTER_ORDER.length]!;
+      const currentIndex = state.group ? GROUP_ORDER.indexOf(state.group) : -1;
+      const next = GROUP_ORDER[(currentIndex + 1) % GROUP_ORDER.length]!;
       return [
         { type: "pop", freq: 380 },
-        { type: "ui", patch: { filter: next, selIndex: 0, view: "browse", category: null } },
+        { type: "ui", patch: { group: next, selIndex: 0, view: "browse", category: null } },
       ];
     }
     case "/":
@@ -142,15 +153,27 @@ export function handleKey(event: KeyEvent, state: UiState, results: Results): Ac
 
     case "ArrowRight":
       if (event.shiftKey) return [{ type: "seek", delta: SEEK_STEP }];
+      if (browsing && isRootShelf(state)) {
+        return [{ type: "pop", freq: 380 }, { type: "ui", patch: { group: GROUP_ORDER[0], selIndex: 0 } }];
+      }
       return browsing ? moveSelection(state, results, 1, 0) : [{ type: "next" }];
     case "ArrowLeft":
       if (event.shiftKey) return [{ type: "seek", delta: -SEEK_STEP }];
+      if (browsing && isRootShelf(state)) {
+        return [{ type: "pop", freq: 380 }, { type: "ui", patch: { group: GROUP_ORDER[0], selIndex: 0 } }];
+      }
       return browsing ? moveSelection(state, results, -1, 0) : [{ type: "previous" }];
     case "ArrowDown":
+      if (browsing && isRootShelf(state)) {
+        return [{ type: "pop", freq: 380 }, { type: "ui", patch: { group: GROUP_ORDER[0], selIndex: 0 } }];
+      }
       return browsing
         ? moveSelection(state, results, 0, 1)
         : [{ type: "volume", delta: -VOLUME_STEP }];
     case "ArrowUp":
+      if (browsing && isRootShelf(state)) {
+        return [{ type: "pop", freq: 380 }, { type: "ui", patch: { group: GROUP_ORDER[0], selIndex: 0 } }];
+      }
       return browsing
         ? moveSelection(state, results, 0, -1)
         : [{ type: "volume", delta: VOLUME_STEP }];