replace state.json cache with bincode state.bin

Faster serialization/deserialization, smaller on disk (4.2MB vs 5.9MB).
Automatic migration from state.json on first load — reads the JSON,
writes state.bin, deletes the old file.

Added list-keys, list-edges, dump-json commands so Python scripts no
longer need to parse the cache directly. Updated bulk-categorize.py
and consolidation-loop.py to use the new CLI commands.

scripts/bulk-categorize.py

@@ -50,13 +50,12 @@ def call_sonnet(prompt: str, timeout: int = 300) -> str:
 
 
 def get_all_keys() -> list[str]:
-    """Get all node keys from state.json."""
-    state_path = MEMORY_DIR / "state.json"
-    if not state_path.exists():
+    """Get all node keys via poc-memory list-keys."""
+    r = subprocess.run(["poc-memory", "list-keys"],
+                       capture_output=True, text=True, timeout=30)
+    if r.returncode != 0:
         return []
-    content = state_path.read_text()
-    keys = re.findall(r'"key":\s*"([^"]*)"', content)
-    return sorted(set(keys))
+    return [k for k in r.stdout.strip().split('\n') if k]
 
 
 def get_unique_files(keys: list[str]) -> list[str]:

scripts/consolidation-loop.py

@@ -167,16 +167,17 @@ def build_triangle_prompt(round_num: int) -> str:
     graph = get_graph_structure()
     status = get_status()
 
-    # Get some node pairs that share neighbors
-    state_path = MEMORY_DIR / "state.json"
-    if state_path.exists():
-        state = state_path.read_text()
-        # Extract some relations
-        relations = re.findall(r'"source_key":\s*"([^"]*)".*?"target_key":\s*"([^"]*)"', state[:20000])
-    else:
-        relations = []
+    # Get edges via CLI
+    r = subprocess.run(["poc-memory", "list-edges"],
+                       capture_output=True, text=True, timeout=30)
+    relations = []
+    if r.returncode == 0:
+        for line in r.stdout.strip().split('\n')[:100]:
+            parts = line.split('\t')
+            if len(parts) >= 2:
+                relations.append((parts[0], parts[1]))
 
-    rel_sample = '\n'.join(f"  {s} → {t}" for s, t in relations[:100])
+    rel_sample = '\n'.join(f"  {s} → {t}" for s, t in relations)
 
     return f"""You are a triangle-closing agent (round {round_num}).