fix: 5 critical/high-priority bugs (auth bypass, relay failures, unbounded recursion, context growth) (#1083)

* fix: address 5 critical and high-priority bugs from issue tracker

- #1033: reject webhook requests when secret is cleared at runtime via
  update_secret(None), preventing auth bypass through SIGHUP hot-swap
- #908: reset consecutive_failures counter on successful SSE stream
  reconnection in relay channel, so circuit breaker counts truly
  consecutive failures
- #975: add depth limit (16) to validate_tool_schema() to prevent
  stack overflow on deeply nested schemas
- #974: add depth limit (8) to resolve_nested() to prevent stack
  overflow on deeply nested capabilities wrappers
- #826: truncate oversized tool outputs (>8KB) in routine lightweight
  loop to prevent unbounded context growth across iterations

Each fix includes a regression test.

Closes #1033, #908, #975, #974, #826

Co-Authored-By: Claude Opus 4.6 <[email protected]>

* fix: 5 more high-priority bugs (routine cache, job signals, input limits)

- #1077: recompute next_fire_at when re-enabling cron routines via web
  toggle, mirroring CLI behavior so cron ticker picks them up
- #1076: refresh event trigger cache after web toggle/delete operations
  so event/system_event routines reflect changes immediately
- #892: remove Stuck from check_signals() stop-states in JobDelegate
  since Stuck is recoverable (Stuck -> InProgress via self-repair)
- #976: truncate oversized description strings in CapabilitiesFile to
  4KB to prevent memory abuse from malicious capabilities files
- #977: drop oversized parameters schema JSON (>64KB) in
  CapabilitiesFile to prevent unbounded memory growth

Each fix includes regression tests where applicable.

Closes #1077, #1076, #892, #976, #977

Co-Authored-By: Claude Opus 4.6 <[email protected]>

* fix: prevent ReDoS in event trigger regex patterns

- #825: use RegexBuilder with 64KB size limit when compiling
  user-supplied event trigger patterns, both at creation time
  (routine tool) and at cache refresh (routine engine)

Note: Rust's regex crate already guarantees O(n) matching, so the
size limit prevents excessive memory use during compilation rather
than catastrophic backtracking at match time.

Closes #825

Co-Authored-By: Claude Opus 4.6 <[email protected]>

* Harden HTTP SSRF IP filtering

* Apply rustfmt after staging merge

---------

Co-authored-by: Claude Opus 4.6 <[email protected]>

src/worker/job.rs

@@ -1108,9 +1108,10 @@ impl<'a> LoopDelegate for JobDelegate<'a> {
             return LoopSignal::InjectMessage(content);
         }
 
-        // Check for terminal or non-progressing state. The loop should stop when the
-        // job has been cancelled, failed, stuck, or already completed — not just the
-        // three states that `is_terminal()` covers (Accepted/Failed/Cancelled).
+        // Check for terminal or post-completion state. The loop should stop when the
+        // job has been cancelled, failed, or already completed — but NOT when Stuck,
+        // because Stuck is recoverable (Stuck -> InProgress via self-repair).
+        // Stopping on Stuck would prevent recovery from resuming the worker (issue #892).
         if let Ok(ctx) = self
             .worker
             .context_manager()
@@ -1120,7 +1121,6 @@ impl<'a> LoopDelegate for JobDelegate<'a> {
                 ctx.state,
                 JobState::Cancelled
                     | JobState::Failed
-                    | JobState::Stuck
                     | JobState::Completed
                     | JobState::Submitted
                     | JobState::Accepted