migrate agent output to capnp store, add provenance tracking

All agent output now goes to the store as nodes instead of
markdown/JSON files. Each node carries a Provenance enum identifying
which agent created it (AgentDigest, AgentConsolidate, AgentFactMine,
AgentKnowledgeObservation, etc — 14 variants total).

Store changes:
- upsert_provenance() method for agent-created nodes
- Provenance enum expanded from 5 to 14 variants

Agent changes:
- digest: writes to store nodes (daily-YYYY-MM-DD.md etc)
- consolidate: reports/actions/logs stored as _consolidation-* nodes
- knowledge: depth DB and agent output stored as _knowledge-* nodes
- enrich: experience-mine results go directly to store
- llm: --no-session-persistence prevents transcript accumulation

Deleted: 14 Python/shell scripts replaced by Rust implementations.

schema/memory.capnp

@@ -48,11 +48,20 @@ enum NodeType {
 }
 
 enum Provenance {
-  manual  @0;
-  journal @1;
-  agent   @2;
-  dream   @3;
-  derived @4;
+  manual                  @0;
+  journal                 @1;
+  agent                   @2;   # legacy catch-all
+  dream                   @3;
+  derived                 @4;
+  agentExperienceMine     @5;
+  agentKnowledgeObservation @6;
+  agentKnowledgePattern   @7;
+  agentKnowledgeConnector @8;
+  agentKnowledgeChallenger @9;
+  agentConsolidate        @10;
+  agentDigest             @11;
+  agentFactMine           @12;
+  agentDecay              @13;
 }
 
 enum Category {