Fix Docker Swarm discovery network name mismatch

- Changed NetworkName from 'chorus_default' to 'chorus_net'
- This matches the actual network 'CHORUS_chorus_net' (service prefix added automatically)
- Fixes discovered_count:0 issue - now successfully discovering all 25 agents
- Updated IMPLEMENTATION-SUMMARY with deployment status

Result: All 25 CHORUS agents now discovered successfully via Docker Swarm API

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

migrations/008_update_council_agent_status_check.down.sql

@@ -0,0 +1,7 @@
+-- Revert council agent assignment status allowance
+ALTER TABLE council_agents
+    DROP CONSTRAINT IF EXISTS council_agents_status_check;
+
+ALTER TABLE council_agents
+    ADD CONSTRAINT council_agents_status_check
+    CHECK (status IN ('pending', 'deploying', 'active', 'failed', 'removed'));