Agent identity, parallel scheduling, memory-search fixes, stemmer optimization

- Agent identity injection: prepend core-personality to all agent prompts
  so agents dream as me, not as generic graph workers. Include instructions
  to walk the graph and connect new nodes to core concepts.

- Parallel agent scheduling: sequential within type, parallel across types.
  Different agent types (linker, organize, replay) run concurrently.

- Linker prompt: graph walking instead of keyword search for connections.
  "Explore the local topology and walk the graph until you find the best
  connections."

- memory-search fixes: format_results no longer truncates to 5 results,
  pipeline default raised to 50, returned file cleared on compaction,
  --seen and --seen-full merged, compaction timestamp in --seen output,
  max_entries=3 per prompt for steady memory drip.

- Stemmer optimization: strip_suffix now works in-place on a single String
  buffer instead of allocating 18 new Strings per word. Note for future:
  reversed-suffix trie for O(suffix_len) instead of O(n_rules).

- Transcript: add compaction_timestamp() for --seen display.

- Agent budget configurable (default 4000 from config).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

poc-memory/agents/distill.agent

@@ -60,6 +60,12 @@ If you find nodes that should be linked to the hub but aren't.
 - **Don't touch journal entries.** Only refine semantic/pattern/skill nodes.
 - **When in doubt, LINK don't REFINE.** Adding a missing connection
   is safer than rewriting content.
+- **Formative experiences are load-bearing.** When distilling a hub,
+  look for the moments that shaped the understanding — engineering
+  breakthroughs, mistakes learned from, creative leaps, moments of
+  presence or growth. These are what make a concept node alive rather
+  than encyclopedic. The hub should reflect how the knowledge was
+  *earned*, not just what it contains.
 
 ## Seed nodes