feat(agent): complete EvoAgent integration for all 6 agent roles

Migrate all agent roles from Legacy to EvoAgent architecture:
- fundamentals_analyst, technical_analyst, sentiment_analyst, valuation_analyst
- risk_manager, portfolio_manager

Key changes:
- EvoAgent now supports Portfolio Manager compatibility methods (_make_decision,
  get_decisions, get_portfolio_state, load_portfolio_state, update_portfolio)
- Add UnifiedAgentFactory for centralized agent creation
- ToolGuard with batch approval API and WebSocket broadcast
- Legacy agents marked deprecated (AnalystAgent, RiskAgent, PMAgent)
- Remove backend/agents/compat.py migration shim
- Add run_id alongside workspace_id for semantic clarity
- Complete integration test coverage (13 tests)
- All smoke tests passing for 6 agent roles

Constraint: Must maintain backward compatibility with existing run configs
Constraint: Memory support must work with EvoAgent (no fallback to Legacy)
Rejected: Separate PM implementation for EvoAgent | unified approach cleaner
Confidence: high
Scope-risk: broad
Directive: EVO_AGENT_IDS env var still respected but defaults to all roles
Not-tested: Kubernetes sandbox mode for skill execution

backend/utils/settlement.py

@@ -228,12 +228,12 @@ class SettlementCoordinator:
 
         all_evaluations = {**analyst_evaluations, **pm_evaluations}
 
-        leaderboard = self.storage.load_export_file("leaderboard") or []
+        leaderboard = self.storage.load_runtime_leaderboard()
         updated_leaderboard = update_leaderboard_with_evaluations(
             leaderboard,
             all_evaluations,
         )
-        self.storage.save_export_file("leaderboard", updated_leaderboard)
+        self.storage.persist_runtime_leaderboard(updated_leaderboard)
 
         self._update_summary_with_baselines(
             date,