fix(R9): trust hierarchy for project attribution

Batch 3, Days 1-3. The core R9 failure was Case F: when the model
returned a registered project DIFFERENT from the interaction's
known scope, the old code trusted the model because the project
was registered. A p06-polisher interaction could silently produce
a p04-gigabit candidate.

New rule (trust hierarchy):
1. Interaction scope always wins when set (cases A, C, E, F)
2. Model project used only for unscoped interactions AND only when
   it resolves to a registered project (cases D, G)
3. Empty string when both are empty or unregistered (case B)

The rule is: interaction.project is the strongest signal because
it comes from the capture hook's project detection, which runs
before the LLM ever sees the content. The model's project guess
is only useful when the capture hook had no project context.

7 case tests (A-G) cover every combination of model/interaction
project state. Pre-existing tests updated for the new behavior.

Host-side script mirrors the same hierarchy using _known_projects
fetched from GET /projects at startup.

Test count: 286 -> 290 (+4 net, 7 new R9 cases, 3 old tests
consolidated).

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

scripts/batch_llm_extract_live.py

@@ -191,15 +191,15 @@ def parse_candidates(raw, interaction_project):
             continue
         mem_type = str(item.get("type") or "").strip().lower()
         content = str(item.get("content") or "").strip()
-        project = str(item.get("project") or "").strip()
-        if not project and interaction_project:
+        model_project = str(item.get("project") or "").strip()
+        # R9 trust hierarchy: interaction scope always wins when set.
+        # Model project only used for unscoped interactions + registered check.
+        if interaction_project:
             project = interaction_project
-        elif project and interaction_project and project != interaction_project:
-            # R9: model hallucinated an unrecognized project — fall back.
-            # The host-side script can't import the registry, so we
-            # check against a known set fetched from the API.
-            if project not in _known_projects:
-                project = interaction_project
+        elif model_project and model_project in _known_projects:
+            project = model_project
+        else:
+            project = ""
         conf = item.get("confidence", 0.5)
         if mem_type not in MEMORY_TYPES or not content:
             continue