feat(core): update backend coordinator, docgov lease, squad workflow and web governance integration

deploy/postgres/migrations/2026-09-09-uq-context-memory-chunk-hash.sql

@@ -0,0 +1,14 @@
+-- 修复 IndexApprovedDocument: ON CONFLICT (chunk_hash) 需要唯一约束
+DELETE FROM context_memory_chunks a
+USING context_memory_chunks b
+WHERE a.chunk_hash IS NOT NULL
+  AND a.chunk_hash <> ''
+  AND a.chunk_hash = b.chunk_hash
+  AND a.id > b.id;
+
+UPDATE context_memory_chunks
+SET chunk_hash = 'legacy_empty_' || id::text
+WHERE chunk_hash IS NULL OR chunk_hash = '';
+
+DROP INDEX IF EXISTS idx_mem_chunks_hash;
+CREATE UNIQUE INDEX IF NOT EXISTS uq_mem_chunks_hash ON context_memory_chunks(chunk_hash);