feat(logging): production-grade logging with context vars, secret masking, and runtime level control

Boot-time logging was a three-line basicConfig stub with no timestamps, no
correlation, and silent drops at every layer of the Telegram send path — a
/random command that delivered text but no media left zero evidence in the
log. This replaces the setup and closes every silent drop encountered end-to-end.

New infrastructure:
- notify_bridge_core.log_context: request_id/command/chat_id/bot_id/dispatch_id
  ContextVars with a bind_log_context() context manager so deep call sites
  (TelegramClient, NotificationDispatcher) inherit the correlation tag without
  threading args through.
- notify_bridge_server.logging_setup: dictConfig-based setup with a
  LogRecordFactory that tags every record, a SecretMaskingFilter that redacts
  /botN:TOKEN plus Authorization/x-api-key/password/secret in messages AND
  tracebacks, a JSON formatter for aggregators, text formatter with grep-friendly
  [req=... cmd=... bot=... chat=... disp=...] prefix, and default dampening
  for sqlalchemy/aiohttp/apscheduler/urllib3/PIL.

Runtime control:
- NOTIFY_BRIDGE_LOG_LEVEL / _FORMAT / _LEVELS env vars (boot).
- DB-backed log_level / log_format / log_levels AppSettings, applied on
  boot after migrations and live via apply_log_levels() when edited in
  the settings UI (format still requires restart, logs a WARN).
- Frontend settings page gains a Logging card (level dropdown, format
  dropdown, per-module overrides); en/ru i18n keys added.

Call-site fixes (/random media-group blind spot and adjacent):
- TelegramClient._fetch_asset: every silent drop now WARN-logs with reason
  (missing url, HTTP non-200, size/dimension limits, ClientError).
- TelegramClient._send_media_group: WARN on "chunk had N items but 0 usable",
  ERROR on sendMediaGroup non-ok/transport with full context; returns
  success=False + "no_items_delivered" instead of success=True with an empty
  message_ids list so callers can distinguish.
- TelegramClient.send_message / _upload_media / _send_from_cache: ERROR on
  non-ok + transport failures with status/code/desc; DEBUG for cache-hit
  fallbacks.
- NotificationDispatcher.dispatch: generates a dispatch_id, binds it, logs
  start/finish with failure count, uses exc_info for target failures.
- commands/handler: missing/failed templates -> ERROR + exc_info; send_reply
  and send_media_group errors upgraded WARNING -> ERROR with chat/error_code
  context; rate-limit and truncation cases logged with full context.
- commands/webhook and services/telegram_poller: bind_log_context(request_id
  =tg:<update_id>, command, chat_id, bot_id), INFO on receive/dispatch/
  completion with duration, exc_info on raise, INFO when commands disabled.
- commands/immich: INFO when album scope is empty; WARN per asset dropped
  from media payload and a summary WARN when "N assets in, 0 out".

packages/server/src/notify_bridge_server/api/app_settings.py

@@ -24,6 +24,10 @@ _SETTING_KEYS = {
     "telegram_asset_cache_max_entries": None,  # LRU cap for both caches
     "supported_locales": None,  # comma-separated locale codes
     "timezone": "NOTIFY_BRIDGE_TIMEZONE",  # IANA tz (e.g. "Europe/Warsaw"); empty = UTC
+    # Logging — applied live via apply_log_levels() when changed.
+    "log_level": "NOTIFY_BRIDGE_LOG_LEVEL",  # DEBUG/INFO/WARNING/ERROR
+    "log_format": "NOTIFY_BRIDGE_LOG_FORMAT",  # text|json (requires restart to switch)
+    "log_levels": "NOTIFY_BRIDGE_LOG_LEVELS",  # module=LEVEL,module2=LEVEL
 }
 
 _DEFAULTS = {
@@ -35,12 +39,20 @@ _DEFAULTS = {
     "telegram_asset_cache_max_entries": "5000",
     "supported_locales": "en,ru",
     "timezone": "UTC",
+    "log_level": "INFO",
+    "log_format": "text",
+    "log_levels": "",
 }
 
 # Settings whose changes require dropping in-memory Telegram caches so the
 # next dispatch rebuilds them with the new parameters. Files are preserved.
 _CACHE_SETTING_KEYS = {"telegram_cache_ttl_hours", "telegram_asset_cache_max_entries"}
 
+# Settings that change logging behaviour. ``log_level`` + ``log_levels`` apply
+# live via apply_log_levels(); ``log_format`` requires a restart because
+# changing it means swapping the handler formatter entirely.
+_LOG_SETTING_KEYS = {"log_level", "log_levels", "log_format"}
+
 
 async def get_setting(session: AsyncSession, key: str) -> str:
     """Read a setting from DB, falling back to env var then default."""
@@ -66,6 +78,9 @@ class SettingsUpdate(BaseModel):
     telegram_asset_cache_max_entries: int | str | None = None
     supported_locales: str | None = None
     timezone: str | None = None
+    log_level: str | None = None
+    log_format: str | None = None
+    log_levels: str | None = None
 
 
 @router.get("")
@@ -95,6 +110,7 @@ async def update_settings(
     old_secret = await get_setting(session, "telegram_webhook_secret")
     old_cache_values = {k: await get_setting(session, k) for k in _CACHE_SETTING_KEYS}
     old_timezone = await get_setting(session, "timezone")
+    old_log_values = {k: await get_setting(session, k) for k in _LOG_SETTING_KEYS}
 
     for key in _SETTING_KEYS:
         value = getattr(body, key, None)
@@ -130,6 +146,25 @@ async def update_settings(
     new_base_url = await get_setting(session, "external_url")
     new_secret = await get_setting(session, "telegram_webhook_secret")
     new_timezone = await get_setting(session, "timezone")
+    new_log_values = {k: await get_setting(session, k) for k in _LOG_SETTING_KEYS}
+
+    # Apply live log-level changes (log_format still needs a restart).
+    if (new_log_values["log_level"] != old_log_values["log_level"]
+            or new_log_values["log_levels"] != old_log_values["log_levels"]):
+        from ..logging_setup import apply_log_levels
+        apply_log_levels(
+            level=new_log_values["log_level"] or None,
+            per_module_levels=new_log_values["log_levels"],
+        )
+        _LOGGER.info(
+            "Log levels updated: root=%s overrides=%r",
+            new_log_values["log_level"], new_log_values["log_levels"],
+        )
+    if new_log_values["log_format"] != old_log_values["log_format"]:
+        _LOGGER.warning(
+            "log_format changed from %r to %r — restart the server for it to take effect",
+            old_log_values["log_format"], new_log_values["log_format"],
+        )
 
     # Cron triggers freeze their timezone at construction time, so a tz change
     # has no effect until the jobs are rebuilt — do that here, before we
@@ -199,7 +234,10 @@ async def _reregister_webhooks(
         if res.get("success"):
             _LOGGER.info("Re-registered webhook for bot %d (%s)", bot.id, bot.name)
         else:
-            _LOGGER.warning(
-                "Failed to re-register webhook for bot %d: %s",
-                bot.id, res.get("error"),
+            # Webhook re-register failure means the bot silently stops
+            # delivering updates — this is operational visibility for an
+            # admin, ERROR is appropriate.
+            _LOGGER.error(
+                "Failed to re-register webhook for bot %d (%s): %s",
+                bot.id, bot.name, res.get("error"),
             )