spec: add BEHAVIOR_SPEC and fix B-01~B-10 (resolved/decay/scoring)

- Add BEHAVIOR_SPEC.md as full system behaviour reference
- B-01: stop auto-archiving resolved buckets in update()
- B-03: keep activation_count as float in calculate_score
- B-04: initialise activation_count=0 on create
- B-05: time score coefficient 0.1 -> 0.02
- B-06: w_time default 2.5 -> 1.5
- B-07: content_weight default 3.0 -> 1.0
- B-08: refresh local meta after auto_resolve
- B-09: user-supplied valence/arousal takes priority over analyze()
- B-10: allow empty domain for feel buckets
- Refresh INTERNALS/README/dashboard accordingly

tests/test_feel_flow.py

@@ -14,11 +14,12 @@
 import os
 import pytest
 import asyncio
+import pytest_asyncio
 
 # Feel flow tests use direct BucketManager calls, no LLM needed.
 
 
-@pytest.fixture
+@pytest_asyncio.fixture
 async def isolated_tools(test_config, tmp_path, monkeypatch):
     """
     Import server tools with config pointing to temp dir.