feat(log): survive a bare deployment and name what each line is about

P0 (foundation) + P1 (diagnostic depth) of the logging plan:

- main.rs initializes the timed builder with a default filter of
  `info,hyper_util=warn,reqwest=warn`. Without RUST_LOG nothing was logged at
  all (env_logger falls back to `error`), so `docker run --env-file .env` was
  silent, and the plain `init` had no timestamps.
- info-and-above lines stop printing user URLs (fetch/send failures, inline
  fetch, bsky's remux warnings). The full URL, the message text and the inline
  query move to `trace`, so a `debug` log can be handed to someone else.
- Lifecycle lines name the chat and the post: sent/failed/queued plus the
  total `ms`, the edit prompt, the channel forward, and every queue line
  (`chat=` + `[key=…]` + per-attempt `ms`, dead-letters included).
- Queue work is visible: `x-media`'s fetch line carries its duration (ugoira
  encode and HLS remux included), and the 300s sweep reports the pending count
  and how overdue the oldest task is — only when the queue is non-empty.
- URL workers are supervised like the queue workers: a panicking worker used
  to die silently and shrink the pool for the rest of the process.
- Degradations that still serve the user (cache/state write or read failures,
  a failed chat action) are `warn`, not `error`.

Verified against the scripted fake-API harness: unset RUST_LOG logs info with
timestamps, `debug` carries no user URL, `trace` does, a cache-hit send logs
`chat=111 in 5ms`, a failing send queues and dead-letters with chat+key, and
the sweep reports the pending retry.

crates/xmedia-bot/src/handlers/inline.rs

@@ -116,11 +116,10 @@ pub async fn inline_query_handler(bot: Bot, query: InlineQuery) -> Result<(), Re
 /// Fetches the post behind an inline query and answers it. The caller has
 /// already applied the debounce. Returns `true` when an answer was sent.
 async fn answer_inline_query(bot: Bot, query: InlineQuery) -> Result<bool, RequestError> {
-    log::debug!(
-        "inline query: {} [key={}]",
-        query.query,
-        log_key(&query.query)
-    );
+    // The query is user input: `debug` keeps only its normalized key, the
+    // text itself is `trace` (same split as the message handler).
+    log::debug!("inline query [key={}]", log_key(&query.query));
+    log::trace!("inline query: {}", query.query);
     // No retries: the debounce plus a 1s/2s backoff would outlast the inline
     // query the answer belongs to.
     match x_media::site::fetch_once(&query.query).await {
@@ -206,7 +205,7 @@ async fn answer_inline_query(bot: Bot, query: InlineQuery) -> Result<bool, Reque
             }
         }
         Ok(None) => {}
-        Err(e) => log::error!("inline fetch {}: {e}", query.query),
+        Err(e) => log::error!("inline fetch [key={}]: {e}", log_key(&query.query)),
     }
     Ok(false)
 }