fix(combo): guarantee combo loops terminate instead of hanging silently

[herjarsa]

Summary

Guarantees that OmniRoute's combo/target loops always terminate with an actionable error instead of dying silently (no response, no log) when an upstream hangs.

Fixes 10 silent-stop gaps (G1–G10) found by auditing every loop that iterates models/combos to resolve a task:

Critical — combo target loop (open-sse/services/combo.ts)

• G1: globalPromise in handleComboChat had no timer — a hung target (per-model timeout disabled) froze the request forever. Added loopSafetyPromise (uses comboTimeoutMs, else a 10-minute hard ceiling COMBO_LOOP_SAFETY_TIMEOUT_MS) to all 3 Promise.race sites; on fire: marks comboExpired, aborts in-flight upstreams, drains in-flight tasks (COMBO_SAFETY_DRAIN_MS), returns 504 with the same aggregated ried: a (500) diagnostics as the regular timeout path.
• G2: task wrapper .catch() now resolves globalPromise with 502 so an unexpected task throw can never leave the post-loop race hanging.
• G3: argetTimeoutRunner logs a warning when comboTargetTimeoutMs <= 0 (per-model timeout disabled).
• G4: handleRoundRobinCombo had no global timeout and no safety net — added
  rSafetyPromise timer (same ceiling),
  rExpired loop guard, Promise.race around each model dispatch, try/catch → 500, and a post-loop 504.
• G9: round-robin retry delay now honors client disconnect (499).

Localized silent exits

• G5 (�utoCombo/chaosEngine.ts): dispatchOnePanelModel hardcoded ok: true — a panel where every model returned 503 was treated as success and the error streamed as a valid answer. Now honors
  es.ok; all-failed branch logs All chaos panel models failed with per-model errors.
• G6 (�utoCombo/pipelineRouter.ts): logs Reflection retries exhausted when the reflection loop burns its budget and still fails.
• G7 (src/lib/evals/evalRunner.ts): rejects catastrophic regex patterns (ReDoS) via safe-regex before est().
• G8 (�utoRefreshDaemon.ts): �alidateCredential swallowed network errors in a bare catch {} (fail-open silent) — now logs provider + error.
• G10 (�atchProcessor.ts): each batch-item dispatch bounded by a 120s wall-clock timeout (withItemDispatchTimeout) so a stuck item fails fast instead of freezing the batch.

Verification

• New regression suite ests/unit/combo-silent-stop-gaps.test.ts — 10/10 pass (hung upstream → 504 in ~130ms; unexpected throw → 502; chaos all-fail → logged; ReDoS regex rejected; batch timeout).
• ests/unit/combo-routing-engine.test.ts + combo-target-timeout-runner.test.ts + pipeline-router.test.ts: 105/105 pass (102 existing + new).
• chaos-executor, �atch-processor, service-batch-processor, �valrunner-builtinsuites-split: 37/37 pass.

pm run typecheck:core clean; ESLint clean on touched files (pre-existing violations in �atchProcessor.ts untouched).

⚠️ base-red inherited: #9985 —
elease/v3.8.50 is currently red upstream; inherited failures are not introduced by this branch.

[diegosouzapw]

Deferido para revalidação do head atual. A rodada anterior registrou um hold de ownership, mas a inspeção atual não confirmou esse worktree; por favor, reconfirme o head e os checks antes da decisão final.