fix: complete B-03/B-08/B-09 and add OMBRE_*_MODEL env vars

- decay_engine: keep activation_count as float (B-03);
  refresh local meta after auto_resolve so resolved_factor
  applies in the same cycle (B-08)
- server.hold(): user-supplied valence/arousal now takes
  priority over analyze() output (B-09)
- utils.load_config: support OMBRE_DEHYDRATION_MODEL
  (with OMBRE_MODEL alias) and OMBRE_EMBEDDING_MODEL
- ENV_VARS.md: document new model env vars
- tests/conftest.py: align fixture with spec-correct weights
  (time_proximity=1.5, content_weight=1.0) and feel subdir layout

server.py

@@ -790,11 +790,16 @@ async def hold(
         }
 
     domain = analysis["domain"]
-    valence = analysis["valence"]
-    arousal = analysis["arousal"]
+    auto_valence = analysis["valence"]
+    auto_arousal = analysis["arousal"]
     auto_tags = analysis["tags"]
     suggested_name = analysis.get("suggested_name", "")
 
+    # --- User-supplied valence/arousal takes priority over analyze() result ---
+    # --- 用户显式传入的 valence/arousal 优先，analyze() 结果作为 fallback ---
+    final_valence = valence if 0 <= valence <= 1 else auto_valence
+    final_arousal = arousal if 0 <= arousal <= 1 else auto_arousal
+
     all_tags = list(dict.fromkeys(auto_tags + extra_tags))
 
     # --- Pinned buckets bypass merge and are created directly in permanent dir ---
@@ -805,8 +810,8 @@ async def hold(
             tags=all_tags,
             importance=10,
             domain=domain,
-            valence=valence,
-            arousal=arousal,
+            valence=final_valence,
+            arousal=final_arousal,
             name=suggested_name or None,
             bucket_type="permanent",
             pinned=True,
@@ -823,8 +828,8 @@ async def hold(
         tags=all_tags,
         importance=importance,
         domain=domain,
-        valence=valence,
-        arousal=arousal,
+        valence=final_valence,
+        arousal=final_arousal,
         name=suggested_name,
     )