feat(jobs): persist async batch job state in PostgreSQL

- Add jobs table to database schema (job_id, status, progress, result_json, etc.)
- Add DatabaseClient methods: create_job, update_job, get_job, list_jobs
- Add mark_stale_jobs_failed() called at startup to handle interrupted jobs
- Refactor _run_batch_job and job endpoints to read/write from PostgreSQL
- Remove in-memory _jobs dict; job state now survives API restarts
- Update init_database.py to list all tables in output

Closes leeworks-agents/SPARC#8

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_api.py

@@ -5,7 +5,7 @@ from datetime import datetime
 from unittest.mock import Mock, patch
 from fastapi.testclient import TestClient
 
-from SPARC.api import app, _analyzer, _jobs
+from SPARC.api import app
 from SPARC.types import CompanyAnalysisResult, BatchAnalysisResult