fix(engine,web): emit iteration_limit_reached/resolved events for dashboard

[jrob5756]

Closes #134

Problem

When a workflow hit its max_iterations limit, the engine prompted the user via a console-only Rich IntPrompt while the web dashboard went silently dark — the last visible event was an agent_completed, then nothing. Users monitoring via --web had no indication that the workflow was paused or what action was needed; they had to switch to the console terminal to discover the prompt.

Backend

Two new event types emitted from _check_iteration_with_prompt and _check_parallel_group_iteration_with_prompt in engine/workflow.py:

• iteration_limit_reached — emitted before the console prompt:

  {
    "agent_name": "reviewer",        // or "group_name" for parallel
    "current_iteration": 20,
    "max_iterations": 20,
    "agent_history": ["architect", "reviewer", "architect", "reviewer", "architect"],
    "possible_loop": true,
    "skip_gates": false
  }

• iteration_limit_resolved — emitted after the prompt:

  {
    "agent_name": "reviewer",
    "continue_execution": true,
    "additional_iterations": 10
  }

The possible_loop heuristic flags when the last 3 history entries are the same agent — a strong signal for a stuck review loop. The skip_gates flag lets subscribers distinguish interactive gates from auto-stop scenarios.

The console subscriber and JSONL log subscriber needed no changes — the existing console prompt continues to drive interactive resolution; the new events are purely additive for downstream consumers.

Frontend

• types/events.ts — added the two event types and matching IterationLimitReachedData / IterationLimitResolvedData interfaces.
• workflow-store.ts — added an iterationLimitGate slice (set on reached, cleared on resolved). Both events produce activity-log and event-log entries on the relevant agent/group node.
• StatusBar.tsx — shows an amber-tinted banner "Iteration limit reached: N/N — awaiting console input" when the gate is open, falling back to normal status text when resolved.

Bundled web/static/ assets rebuilt via npm run build (the standard build pipeline).

Tier-1 fix only

This PR delivers the dashboard-visibility half of the issue (emit events, render the gate). It does not make the gate web-resolvable from the dashboard — the user still answers via the console prompt. Web-resolvable iteration gates would require bidirectional WebSocket coordination similar to human gates and is out of scope for this fix.

Tests

• New tests/test_engine/test_iteration_limit_events.py with 3 cases:
  • reached event payload + skip_gates flag + possible_loop heuristic
  • resolved event in skip_gates mode (auto-stop)
  • reached event emitted strictly before resolved
• make lint clean.
• Full suite: 2374 passed, 9 skipped (1 unrelated live Copilot integration test excluded — same as in fix(schema): forbid extra fields on AgentDef/ParallelGroup/ForEachDef/WorkflowConfig #159 / fix(providers): pretty-print tool args/results in dashboard events #161).

Verification

In a workflow with a tight max_iterations limit and --web, the dashboard now:

1. Emits iteration_limit_reached → StatusBar turns amber: "Iteration limit reached: reviewer 20/20 — awaiting console input"
2. User responds in console → iteration_limit_resolved clears the gate and StatusBar returns to normal.