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.

AGENTS.md

@@ -74,7 +74,7 @@ Docker: `docker build -t tgxmb .` then `docker run --rm -d --name tgxmb --env-fi
 - **Serde**: per-site `model.rs` are pure `Deserialize` DTOs mirroring API JSON; site structs in `interface.rs` have private fields, a `caption()` builder, and `impl From<SiteStruct> for Fetched`. Persisted payloads use internally-tagged enums (`#[serde(tag = "kind")]` / `type`).
 - **Naming**: module-per-concern, snake_case files, `CamelCase` types, `snake_case` fns. `//!` module docs and `///` docs on non-obvious logic (syndication token, ugoira encoding, `display_text_range`).
 - **Retries**: only `x-media::site::fetch` retries (3 attempts, `1 << attempt` backoff, HTTP errors only); `site::fetch_once` is the same code path with a single attempt, used by inline queries whose answer window is shorter than the backoff. Queue retries are explicit `QueueError::Retryable` with computed delay (`retry_delay_seconds`).
-- Logging via `log` macros (`pretty_env_logger`, level from `RUST_LOG`). Level convention: `info` = lifecycle + per-post business results (`sent`/`forwarded`/`copied`), admin/operator actions and anomalies (fallback, retry enqueue, dead-letter is `error`); `debug` = per-request detail (message/command/URL extraction, `fetching`/`fetched`, batch sends, queue processing, photo processing, inline queries). Full user-submitted URLs and message text only appear at `debug`; at `info` and above links are printed via the normalized cache key (`handlers::log_key`, e.g. `[key=twitter:123...]`) so logs stay short and do not echo user data.
+- Logging via `log` macros (`pretty_env_logger`, level from `RUST_LOG`). `main.rs` initializes the **timed** builder with a default filter of `info,hyper_util=warn,reqwest=warn` when `RUST_LOG` is unset: the plain `init` had no timestamps and fell back to `error`, so a deployment that forgot the variable logged nothing at all, and at `debug` the HTTP client's own lines outnumbered the bot's two to one. An explicit `RUST_LOG` overrides the default wholesale. Level convention: `info` = lifecycle + per-post business results (`sent`/`forwarded`/`copied`, with `chat=` and the total `ms`), admin/operator actions and anomalies (fallback, retry enqueue, dead-letter is `error`); `debug` = per-request detail (URL extraction, `fetching`/`fetched` with the fetch duration, batch sends, queue processing with the row's `chat=`/`key=` and per-attempt `ms`, photo processing, inline queries); `trace` = user data (the full URL, the message text, the inline query). At `debug` and above links are printed via the normalized cache key (`handlers::log_key`, e.g. `[key=twitter:123...]`), so a `debug` log can be shared without echoing what users pasted, and degradations that leave the user served (a failed cache read/write, a failed chat action) are `warn`, not `error`. The only queue/sweep aggregate is the 300 s sweep's queue line, and it speaks only when the queue is non-empty.
 
 ## Important Files