docs(architecture): add memory-driven architecture & tool usage planning

Planning documents for memory service integration:

MEMORY_DRIVEN_ARCHITECTURE.md:
- Current state machine architecture (10 phases, 80 tasks)
- Memory service integration points & flow diagrams
- Activity usage per phase (T0-T10)
- Prompt optimization with memory context
- Retry policy enhancement via memory
- Complete flow diagrams & context hierarchy
- Skills and context consumption model

TOOL_USAGE_AND_SKILLS.md:
- Poimen tool landscape (6 categories)
- WorkflowDef builder, event log, executor patterns
- Verifier/judge/model provider integration
- Storage abstraction (EventLog + BlobStore)
- Skills ingestion strategy (4 phases)
- YAML skills registry example
- Tool-skill dependency matrix
- End-to-end execution scenario with memory

Both docs include:
- Flow diagrams
- Code examples
- Integration patterns
- Next steps for implementation

k8s/worker-deployment.yaml

@@ -13,7 +13,7 @@ spec:
       labels:
         app: poimen-worker
       annotations:
-        git-commit: "c2df8a0"  # ✅ Updated on each push, triggers rolling restart
+        git-commit: "4982c04"  # ✅ Updated on each push, triggers rolling restart
         deployment-date: "2026-08-29"
     spec:
       containers: