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/commands/immich/common.py

@@ -144,6 +144,7 @@ def _format_assets(
         # other's cached file_ids (which is what made the cache look empty
         # from the WebUI after running /random).
         media_items: list[dict[str, Any]] = []
+        dropped = 0
         for asset in assets:
             asset_id = asset.get("id", "")
             asset_type = (asset.get("type") or "").upper()
@@ -156,6 +157,20 @@ def _format_assets(
             )
             if entry is not None:
                 media_items.append(entry)
+            else:
+                dropped += 1
+                _LOGGER.warning(
+                    "Dropped asset from /%s media payload: id=%s type=%s (empty preview URL)",
+                    cmd, asset_id, asset_type,
+                )
+        if not media_items and assets:
+            # All assets were filtered out before reaching Telegram. The user
+            # will see the text reply but no media — surface it here so the
+            # log shows WHY the media group ended up empty.
+            _LOGGER.warning(
+                "/%s media payload empty: %d asset(s) in, 0 out (all dropped)",
+                cmd, len(assets),
+            )
         # Return text message + media items — text is sent first, media as reply
         return {"text": text, "media": media_items}