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/tools/builtin/http.rs

@@ -214,6 +214,7 @@ fn is_disallowed_ipv4(v4: &Ipv4Addr) -> bool {
         || v4.is_multicast()
         || v4.is_unspecified()
         || *v4 == Ipv4Addr::new(169, 254, 169, 254)
+        || (v4.octets()[0] == 100 && (v4.octets()[1] & 0xC0) == 64)
 }
 
 fn is_disallowed_ip(ip: &IpAddr) -> bool {
@@ -913,6 +914,8 @@ mod tests {
         assert!(is_disallowed_ip(&IpAddr::V4(Ipv4Addr::new(
             169, 254, 169, 254
         ))));
+        // Carrier-grade NAT
+        assert!(is_disallowed_ip(&IpAddr::V4(Ipv4Addr::new(100, 64, 0, 1))));
         // Public
         assert!(!is_disallowed_ip(&IpAddr::V4(Ipv4Addr::new(8, 8, 8, 8))));
     }

src/tools/builtin/routine.rs

@@ -199,9 +199,13 @@ impl Tool for RoutineCreateTool {
                             "event trigger requires 'event_pattern'".to_string(),
                         )
                     })?;
-                // Validate regex
-                regex::Regex::new(pattern)
-                    .map_err(|e| ToolError::InvalidParameters(format!("invalid regex: {e}")))?;
+                // Validate regex with size limit to prevent ReDoS (issue #825)
+                regex::RegexBuilder::new(pattern)
+                    .size_limit(64 * 1024)
+                    .build()
+                    .map_err(|e| {
+                        ToolError::InvalidParameters(format!("invalid or too complex regex: {e}"))
+                    })?;
                 let channel = params
                     .get("event_channel")
                     .and_then(|v| v.as_str())