fix(mem0-plugin): fix 3 critical + 5 important issues from review

Critical fixes:
- C1: Pin/dream update_memory now reads content first via get_memory
  before updating, preventing metadata-only calls that wipe content
- C2: SessionStart memory count uses GET /v3/memories/?page_size=1 for
  real count from pagination envelope instead of search limit=100
- C3: on_task_completed.sh uses ${MEM0_PROJECT_ID:-unknown} to avoid
  crash when identity resolution fails under set -u

Important fixes:
- I1: session_stats.py tracks recent_ids (memory IDs + timestamps) for
  /mem0:forget undo support. Capped at 50 entries.
- I2: /mem0:health --deep mode adds memory quality analysis: duplicate
  detection, stale entry scan, contradiction flags, orphan tagging
- I3: /mem0:stats ASCII histogram for category distribution with bar
  chart, sorted by count descending
- I4: mem0-mcp skill documents access counter pattern: get_memory then
  update_memory to track which memories are actually used
- I5: on_pre_commit.py reads COMMIT_EDITMSG first (current commit),
  falls back to HEAD only if EDITMSG unavailable

Tests: 91 -> 94 (3 new for recent_ids tracking)

mem0-plugin/scripts/on_pre_commit.py

@@ -36,6 +36,25 @@ except ImportError:
 
 
 def get_commit_message() -> str:
+    """Read the current commit message from COMMIT_EDITMSG (pre-commit context).
+
+    Falls back to HEAD's message if COMMIT_EDITMSG doesn't exist yet
+    (e.g., when invoked outside the git hook context).
+    """
+    try:
+        git_dir = subprocess.run(
+            ["git", "rev-parse", "--git-dir"],
+            capture_output=True, text=True, timeout=5,
+        )
+        if git_dir.returncode == 0:
+            editmsg = os.path.join(git_dir.stdout.strip(), "COMMIT_EDITMSG")
+            if os.path.isfile(editmsg):
+                with open(editmsg) as f:
+                    first_line = f.readline().strip()
+                    if first_line and not first_line.startswith("#"):
+                        return first_line
+    except Exception:
+        pass
     try:
         result = subprocess.run(
             ["git", "log", "-1", "--format=%s", "HEAD"],

mem0-plugin/scripts/on_session_start.sh

@@ -39,29 +39,25 @@ import json, os, urllib.request, urllib.error
 api_key = os.environ.get('MEM0_API_KEY', '')
 user_id = os.environ.get('MEM0_RESOLVED_USER_ID', 'default')
 app_id = os.environ.get('MEM0_PROJECT_ID', '')
-body = json.dumps({
-    'query': 'project context',
-    'user_id': user_id,
-    'filters': {'AND': [{'user_id': user_id}, {'app_id': app_id}]},
-    'limit': 100,
-}).encode()
+# Use GET /v3/memories/ with page_size=1 to get total count from pagination
+# without fetching all memories. The response envelope includes a count field.
+params = f'user_id={user_id}&app_id={app_id}&page_size=1'
 req = urllib.request.Request(
-    'https://api.mem0.ai/v3/memories/search/',
-    data=body,
-    headers={'Authorization': f'Token {api_key}', 'Content-Type': 'application/json'},
-    method='POST',
+    f'https://api.mem0.ai/v3/memories/?{params}',
+    headers={'Authorization': f'Token {api_key}'},
+    method='GET',
 )
 try:
     with urllib.request.urlopen(req, timeout=5) as r:
         data = json.loads(r.read())
-        if isinstance(data, list):
-            results = data
+        if isinstance(data, dict) and 'count' in data:
+            print(data['count'])
+        elif isinstance(data, list):
+            print(len(data))
         elif isinstance(data, dict) and 'results' in data:
-            results = data['results']
+            print(len(data['results']))
         else:
-            print('?'); raise SystemExit
-        n = len(results)
-        print(f'{n}+' if n >= 100 else str(n))
+            print('?')
 except Exception:
     print('?')
 " 2>/dev/null || echo "?")

mem0-plugin/scripts/on_task_completed.sh

@@ -7,18 +7,21 @@
 # Input:  JSON on stdin with task_id, task_subject, task_description
 # Output: Text that becomes feedback to the model (exit 0)
 
-set -euo pipefail
+# Intentionally omit -e so the reminder always emits even if identity resolution fails.
+set -uo pipefail
 
 if [ -n "${MEM0_DEBUG:-}" ]; then
   mkdir -p "$HOME/.mem0" && exec 2>>"$HOME/.mem0/hooks.log"
 fi
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
-. "$SCRIPT_DIR/_identity.sh" || true
+. "$SCRIPT_DIR/_identity.sh" 2>/dev/null || true
 
 INPUT=$(cat)
 TASK_SUBJECT=$(echo "$INPUT" | jq -r '.task_subject // "unknown task"' 2>/dev/null || echo "unknown task")
 
+_PROJECT="${MEM0_PROJECT_ID:-unknown}"
+
 cat <<EOF
 Task completed: "$TASK_SUBJECT"
 
@@ -31,7 +34,7 @@ Extract key learnings from this completed task and store them using the mem0 \`a
 
 Memories can be as detailed as needed — include full context, reasoning, code snippets, and examples.
 Only store genuinely useful learnings — skip if the task was trivial.
-Include \`app_id\` = \`"$MEM0_PROJECT_ID"\` as a top-level parameter in every \`add_memory\` call (not in metadata).
+Include \`app_id\` = \`"$_PROJECT"\` as a top-level parameter in every \`add_memory\` call (not in metadata).
 EOF
 
 exit 0

mem0-plugin/scripts/session_stats.py

@@ -42,17 +42,21 @@ def _save(stats: dict) -> None:
         json.dump(stats, f)
 
 
+MAX_RECENT_IDS = 50
+
+
 def init() -> None:
     _save({
         "adds": 0,
         "searches": 0,
         "categories": [],
         "category_counts": {},
+        "recent_ids": [],
         "started": datetime.now().isoformat(),
     })
 
 
-def record_add(category: str = "") -> None:
+def record_add(category: str = "", memory_id: str = "") -> None:
     stats = _load()
     stats["adds"] = stats.get("adds", 0) + 1
     if category:
@@ -60,6 +64,11 @@ def record_add(category: str = "") -> None:
             stats.setdefault("categories", []).append(category)
         counts = stats.setdefault("category_counts", {})
         counts[category] = counts.get(category, 0) + 1
+    if memory_id:
+        recent = stats.setdefault("recent_ids", [])
+        recent.append({"id": memory_id, "category": category, "ts": datetime.now().isoformat()})
+        if len(recent) > MAX_RECENT_IDS:
+            stats["recent_ids"] = recent[-MAX_RECENT_IDS:]
     _save(stats)
 
 
@@ -108,7 +117,8 @@ def main() -> int:
         init()
     elif cmd == "add":
         category = sys.argv[2] if len(sys.argv) > 2 else ""
-        record_add(category)
+        memory_id = sys.argv[3] if len(sys.argv) > 3 else ""
+        record_add(category, memory_id)
     elif cmd == "search":
         record_search()
     elif cmd == "peek":