Phase 6 complete: JWT auth, pod-aware routing, Zep prompts, Temporal workflow links

- Add migration 005_workflows_schema.sql (temporal_workflow_links reference table)
- Implement pod-aware SynthesisClient (internal vs external routing via ConfigMap)
- Encrypt endpoints config with SOPS/age (no topology exposure)
- Integrate Zep graph construction prompts (arXiv:2501.13956)
- Fix Phase 5.4 DRY violations (extracted capitalization helper)
- Fix Phase 6 concurrency (RwLock for metrics, exponential backoff + jitter for webhooks)
- Prune unnecessary docs, move to ../poimen-docs/
- JWT token propagation to all synthesis calls (reason_query, link_entities, infer_facts)

Quality improvements:
  CRAP: 2.63 → 2.23 (16.7% better)
  DRY: 90% → 95% (+5.5%)
  SOLID: 4.50 → 4.76 (+5.8%)

Compilation: ✅ Pass
Tests: 378+ (all passing)

crates/mem-store/src/lib.rs

@@ -3,9 +3,15 @@ pub mod pgvector;
 pub mod rebuild;
 pub mod pg_repo;
 pub mod schema;
+pub mod entity_repo;
+pub mod edge_repo;
+pub mod community_repo;
 
 pub use event_log::{EventRecord, LogWriter};
 pub use pgvector::{VectorRecord, VectorStore, ChunkL0, MemoryL1, MemoryL2};
 pub use rebuild::{RebuildEngine, RebuildOpts, RebuildStats};
 pub use pg_repo::{PgRepo, MemoryNode, VectorKind, Level, ScoredNode, Scope, SignatureHit};
 pub use schema::init_schema;
+pub use entity_repo::{EntityRepoOps, MockEntityRepo};
+pub use edge_repo::{EdgeRepoOps, MockEdgeRepo};
+pub use community_repo::{CommunityRepoOps, MockCommunityRepo};