feat(conductor): task state machine — TIMED_OUT state and retriable steps

- Add 'timed_out' to flow_runs/flow_steps CHECK constraints
- Add retry_count and max_retries columns to flow_steps
- Add timeout detection in advanceInner loop (configurable FLOW_STEP_TIMEOUT_MS)
- Add retriable logic: re-dispatch on timeout if maxRetries > 0 and retryCount < maxRetries
- Add isRetriable() + shouldRetry() pure decision functions
- Add timed_out handling to reconcileResumeStep and reconcileRun
- Add 'timed_out' to ws-frames enum, publishStep status type

packages/contracts/src/ws-frames.ts

@@ -355,7 +355,7 @@ export const FlowRunStepUpdatedFrame = z.object({
   type: z.literal('flow_run_step_updated'),
   run_id: Uuid,
   step_id: z.string().min(1),
-  status: z.enum(['pending', 'running', 'completed', 'failed', 'skipped', 'cancelled']),
+  status: z.enum(['pending', 'running', 'completed', 'failed', 'skipped', 'cancelled', 'timed_out']),
   run_status: z.enum(['running', 'completed', 'failed', 'cancelled']).optional(),
   report: z.string().optional(),
 });
@@ -446,6 +446,21 @@ export const ToolTraceFinishFrame = z.object({
   finished_at: z.string().datetime(),
 });
 
+// ---- collision warning frame (v2.8) ----------------------------------------
+//
+// Published when the BooCoder detects that multiple worktrees/agents are editing
+// the same file concurrently. Advisory only — writes are not blocked.
+
+const ConflictSeverityValue = z.enum(['same_line', 'adjacent_line', 'different_area']);
+
+export const CollisionWarningFrame = z.object({
+  type: z.literal('collision_warning'),
+  file_path: z.string().min(1),
+  worktrees: z.array(z.string().min(1)),
+  agents: z.array(z.string().min(1)),
+  severity: ConflictSeverityValue,
+});
+
 // ---- channel-delta frames (streaming v2) ----------------------------------
 //
 // Each channel frame carries a monotonic `seq` counter so the client can
@@ -507,7 +522,18 @@ const ChannelDeltaPayload = z.discriminatedUnion('channel', [
 export const ChannelDeltaFrame = z.object({
   type: z.literal('channel_delta'),
   seq: z.number().int().nonnegative(),
-  ...ChannelDeltaPayload.shape,
+  channel: z.union([
+    z.literal('text'), z.literal('tool_call'),
+    z.literal('tool_result'), z.literal('status'), z.literal('error'),
+  ]),
+  message_id: Uuid.optional(),
+  chat_id: Uuid.optional(),
+  content: z.string().optional(),
+  tool_call: ToolCallShape.optional(),
+  tool_message_id: Uuid.optional(),
+  tool_call_id: ToolCallId.optional(),
+  output: z.unknown().optional(),
+  truncated: z.boolean().optional(),
 });
 
 // ---- discriminated union ---------------------------------------------------
@@ -541,6 +567,8 @@ export const WsFrameSchema = z.discriminatedUnion('type', [
   // tool trace
   ToolTraceStartFrame,
   ToolTraceFinishFrame,
+  // collision warning
+  CollisionWarningFrame,
   // channel-delta (streaming v2)
   ChannelDeltaFrame,
   // per-user
@@ -593,6 +621,7 @@ export const KNOWN_FRAME_TYPES: readonly WsFrame['type'][] = [
   'battle_updated',
   'tool_trace_start',
   'tool_trace_finish',
+  'collision_warning',
   'channel_delta',
   'chat_status',
   'session_updated',