Remove dead code

- wire.with_figure: the device uses dataclasses.replace directly.
- DeviceConnected/DeviceDisconnected: emitted, never subscribed to, and a duplicate
  of ConnectionChanged(target="firmware").
- ScreenService.toggle(): never called.
- GET /api/lirc (LircConfigOut, api.lircConfig): no front-end reads it.
- POST /api/volume's delta_percent (api.nudgeVolume): no front-end sends it.
- LibraryCache.shrink_stored_covers: a one-off migration that re-read every cover
  header on every scan. _INDEX_VERSION 7 rebuilds any cache that could still need it.
- Firmware: the MFRC522 library and its unused globals (lib/nfc/rc522.c is the
  driver in use), and mfrc_version.h, a reader test sketch nothing included.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/api/client.ts

@@ -4,7 +4,6 @@ import type {
   Album,
   HaConfig,
   HaEntityState,
-  LircConfig,
   PlayerState,
   RemoteMapping,
   RemoteSlotInput,
@@ -55,9 +54,6 @@ async function fetchOrNullOnError<T>(path: string): Promise<T | null> {
 /** `null` means the room-control page isn't configured, not an error. */
 const fetchHaConfig = (): Promise<HaConfig | null> => fetchOrNullOn404<HaConfig>("/ha");
 
-/** `null` means the IR remote isn't configured, not an error. */
-const fetchLircConfig = (): Promise<LircConfig | null> => fetchOrNullOn404<LircConfig>("/lirc");
-
 /** `null` means the typing game isn't configured, not an error - the tab still shows,
  * just with a "not set up" placeholder instead of a lesson map. */
 const fetchTippenCurriculum = (): Promise<TippenCurriculum | null> =>
@@ -96,7 +92,6 @@ export const api = {
   previous: () => post("/previous"),
   seek: (position: number) => post("/seek", { position }),
   setVolume: (percent: number) => post("/volume", { percent }),
-  nudgeVolume: (deltaPercent: number) => post("/volume", { delta_percent: deltaPercent }),
   /** One step of the IR remote's volume keys per unit, in the device's own increment. */
   stepVolume: (steps: number) => post("/volume", { steps }),
   toggleScreen: () => post("/screen/toggle"),
@@ -118,7 +113,6 @@ export const api = {
 
   trackDetail: fetchTrackDetail,
 
-  lircConfig: fetchLircConfig,
   pressRemote: (digit: string) => post(`/remote/press/${digit}`),
   remoteMapping: () => request<RemoteMapping>("/remote/mapping"),
   saveRemoteMapping: (slots: Record<string, RemoteSlotInput>) =>

web/src/api/types.ts

@@ -171,11 +171,6 @@ export interface RemoteSlotInput {
   track_index?: number;
 }
 
-/** Presence-only, like `HaConfig` - there is nothing secret in a host/port. */
-export interface LircConfig {
-  connected: boolean;
-}
-
 // --------------------------------------------------------------------------- tippen
 //
 // The typing game. `null` from `GET /tippen/curriculum` means the whole feature isn't