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

deploy/systemd/evotraders.service

@@ -1,6 +1,14 @@
 [Unit]
 Description=大时代 Production Service
 After=network.target
+# COMPATIBILITY_SURFACE: stable
+# OWNER: ops-team
+# SEE: docs/legacy-inventory.md#gateway-first-production-example
+#
+# This systemd unit runs the gateway-first production topology.
+# It executes scripts/run_prod.sh which launches backend.main as the
+# primary gateway/runtime process. For split-service deployment topology,
+# see docs/current-architecture.md and deploy/README.md
 
 [Service]
 Type=simple