phase3(契约层): protocol.ts + 落盘状态 + store 失败策略/判活原语

多进程执行解耦的 Phase 0 共享契约（worker 与 daemon 都 import 它）：
- executor/protocol.ts: JobSpec(daemon→worker 唯一输入) + OutboxRecord(worker→daemon) +
  文件 IO(job/outbox/heartbeat) + isWorkerAlive(心跳为主/boot 窗口 pid 兜底/防 pid 复用)
- schema+db+types+mappers: runs.worker_pid/last_seq、tasks.next_eligible_at(持久化退避)
- store: failTaskAttempt(失败/重试策略唯一落点) + setNextEligibleAt/setWorkerPid/setLastSeq +
  countExecuting + executingWithLatestExecutorRun + reconcileInterrupted(isAlive 注入,默认保守回收)

纯增量,140 测试全绿。worker.ts/pipeline.ts(worker 侧) 与 orchestrator/ingest/index(daemon 侧) 待接。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/store/mappers.ts

@@ -16,6 +16,7 @@ export interface TaskRow {
   title: string; complexity: string; status: string; priority: number;
   deps: string; plan: string | null; spec: string | null; operations: string | null;
   result: string | null; assignee: string | null; retry_baseline: number;
+  next_eligible_at: string | null;
   created_at: string; updated_at: string;
   source_ref: string | null;
 }
@@ -27,6 +28,7 @@ export interface RunRow {
   id: string; task_id: string; kind: string; worktree: string | null; branch: string | null;
   status: string; started_at: string; ended_at: string | null;
   transcript_ref: string | null; claude_session_id: string | null; error: string | null;
+  worker_pid: number | null; last_seq: number;
 }
 export interface EventRow {
   id: string; project_id: string; task_id: string | null; type: string; payload: string; at: string;
@@ -68,6 +70,7 @@ export function rowToTask(r: TaskRow, approvals: ApprovalRecord[] = []): Task {
     plan: r.plan, spec: r.spec, operations: r.operations,
     approvals, result: r.result ? parseResult(r.result) : null,
     assignee: r.assignee as Task['assignee'], retryBaseline: r.retry_baseline ?? 0,
+    nextEligibleAt: r.next_eligible_at ?? null,
     createdAt: r.created_at, updatedAt: r.updated_at,
   };
 }
@@ -85,6 +88,7 @@ export function rowToRun(r: RunRow): Run {
     worktree: r.worktree, branch: r.branch, status: r.status as RunStatus,
     startedAt: r.started_at, endedAt: r.ended_at,
     transcriptRef: r.transcript_ref, claudeSessionId: r.claude_session_id, error: r.error,
+    workerPid: r.worker_pid ?? null, lastSeq: r.last_seq ?? 0,
   };
 }