Add IR remote control (LIRC) with a number-key content mapping

Adds a TCP client for lircd's classic protocol: play/pause/next/prev/
volume/mute map to the same intents every other front-end already
emits, and number keys 0-9 play an assigned album/audiobook from the
start or a podcast show's newest episode, resolved fresh on every
press. The mapping is configured in config.yml and editable from the
frontend: a small "Taste zuweisen" button on the play screen (or the
A+digit keyboard shortcut) opens a 10-key picker to assign whatever is
currently playing.

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

python-backend/musicmouse/config.py

@@ -33,18 +33,24 @@ __all__ = [
     "SIMULATE",
     "Config",
     "ConfigError",
+    "Digit",
     "FigureColors",
     "FigureConfig",
     "GeneralConfig",
     "HaConfig",
     "HaDeviceConfig",
     "LibraryConfig",
+    "LircConfig",
     "MqttConfig",
+    "RemoteSlotConfig",
     "WebConfig",
     "format_validation_error",
     "load_config",
 ]
 
+#: Number keys on the IR remote, as lircd's ``BTN_0``..``BTN_9`` map to them.
+type Digit = Literal["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]
+
 DEFAULT_AUDIO_EXTENSIONS = (".mp3", ".ogg", ".oga", ".opus", ".flac", ".wav", ".m4a", ".aac")
 
 #: Stand-in value for ``serial_port`` and ``alsa_device``. Running without the mouse or
@@ -133,6 +139,22 @@ class MqttConfig(_Strict):
     reconnect_interval: float = Field(default=10.0, gt=0)
 
 
+class LircConfig(_Strict):
+    """TCP client for lircd's classic network protocol - see ``ansible/roles/pi_lirc``.
+
+    Omit the whole section to run without an IR remote.
+    """
+
+    host: str
+    #: This deployment's lircd listens on 2222 (see the ansible role); lircd's own
+    #: default is 8765, so this is worth overriding rather than assuming.
+    port: int = Field(default=2222, ge=1, le=65535)
+    #: Only button events from this remote are acted on - other remotes registered
+    #: with the same lircd (an LED remote, say) are ignored.
+    remote_name: str = "Hauppauge"
+    reconnect_interval: float = Field(default=5.0, gt=0)
+
+
 class LibraryConfig(_Strict):
     """Where the music lives.
 
@@ -221,6 +243,7 @@ class GeneralConfig(_Strict):
     mqtt: MqttConfig | None = None
     web: WebConfig | None = None
     ha: HaConfig | None = None
+    lirc: LircConfig | None = None
 
     min_volume: int = Field(default=0, ge=0, le=200)
     max_volume: int = Field(default=100, ge=0, le=200)
@@ -262,9 +285,26 @@ class FigureConfig(_Strict):
     kind: Literal["music", "book"] = "music"
 
 
+class RemoteSlotConfig(_Strict):
+    """What a number key on the IR remote plays.
+
+    ``"album"``: ``target`` is an ``Album.id``, always started from track 0 - a music
+    album or an audiobook. ``"series"``: ``target`` is a podcast show name (an
+    ``Album.series``); resolved to that show's newest episode fresh on every press,
+    since a podcast show is not itself one playable thing in this library - each
+    episode is its own album.
+    """
+
+    target_kind: Literal["album", "series"]
+    target: str
+
+
 class Config(_Strict):
     general: GeneralConfig
     figures: dict[str, FigureConfig] = Field(min_length=1)
+    #: Number key (0-9) -> what it plays. Empty by default: a fresh install has no
+    #: assignments, and that is not an error.
+    remote: dict[Digit, RemoteSlotConfig] = Field(default_factory=dict)
 
     @model_validator(mode="after")
     def _check_unique_tag_ids(self) -> Self: