fix(R7/R9): overlap-density ranking + project trust-preservation

R7: ranking scorer now uses overlap-density (overlap_count /
memory_token_count) as primary key instead of raw overlap count.
A 5-token memory with 3 overlapping tokens (density 0.6) now beats
a 40-token overview memory with 3 overlapping tokens (density 0.075)
at the same absolute count. Secondary: absolute overlap. Tertiary:
confidence. Targeting p06-firmware-interface harness fixture.

R9: when the LLM extractor returns a project that differs from the
interaction's known project, it now checks the project registry.
If the model's project is a registered canonical ID, trust it. If
not (hallucinated name), fall back to the interaction's project.
Uses load_project_registry() for the check. The host-side script
mirrors this via an API call to GET /projects at startup.

Two new tests: test_parser_keeps_registered_model_project and
test_parser_rejects_hallucinated_project.

Test count: 280 -> 281.

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

scripts/batch_llm_extract_live.py

@@ -100,6 +100,22 @@ def set_last_run(base_url, timestamp):
         pass
 
 
+_known_projects: set[str] = set()
+
+
+def _load_known_projects(base_url):
+    """Fetch registered project IDs from the API for R9 validation."""
+    global _known_projects
+    try:
+        data = api_get(base_url, "/projects")
+        _known_projects = {p["id"] for p in data.get("projects", [])}
+        for p in data.get("projects", []):
+            for alias in p.get("aliases", []):
+                _known_projects.add(alias)
+    except Exception:
+        pass
+
+
 def extract_one(prompt, response, project, model, timeout_s):
     """Run claude -p on one interaction, return parsed candidates."""
     if not shutil.which("claude"):
@@ -178,6 +194,12 @@ def parse_candidates(raw, interaction_project):
         project = str(item.get("project") or "").strip()
         if not project and 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
         conf = item.get("confidence", 0.5)
         if mem_type not in MEMORY_TYPES or not content:
             continue
@@ -202,8 +224,9 @@ def main():
     parser.add_argument("--model", default=DEFAULT_MODEL)
     args = parser.parse_args()
 
+    _load_known_projects(args.base_url)
     since = args.since or get_last_run(args.base_url)
-    print(f"since={since or '(first run)'}  limit={args.limit}  model={args.model}")
+    print(f"since={since or '(first run)'}  limit={args.limit}  model={args.model}  known_projects={len(_known_projects)}")
 
     params = [f"limit={args.limit}"]
     if since: