feat(mem0-plugin): smart retrieval, citations, pre-commit capture (Tier 7)

Smart retrieval tier:
- on_user_prompt.sh: stack-trace detection (auto-searches anti_patterns on errors)
- on_user_prompt.sh: file-aware retrieval (extracts file paths, suggests scoped search)
- on_user_prompt.sh: recency boost guidance for state-related queries
- mem0-mcp/SKILL.md: inline citation format [mem0:<8char_id>]
- on_pre_commit.py: captures staged diff as commit_context memory via REST API

mem0-plugin/scripts/on_pre_commit.py

@@ -0,0 +1,116 @@
+#!/usr/bin/env python3
+"""Pre-commit memory capture.
+
+Captures a summary of staged changes as a mem0 memory before each commit.
+Runs as a background fire-and-forget call — never blocks the commit.
+
+Usage:
+  git diff --cached --stat | python3 on_pre_commit.py
+  # or with full diff:
+  git diff --cached | python3 on_pre_commit.py --full
+
+Env vars required: MEM0_API_KEY (or CLAUDE_PLUGIN_OPTION_MEM0_API_KEY)
+Env vars optional: MEM0_RESOLVED_USER_ID, MEM0_PROJECT_ID, MEM0_BRANCH
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import subprocess
+import sys
+import urllib.error
+import urllib.request
+
+sys.path.insert(0, os.path.dirname(__file__))
+from _identity import resolve_api_key, resolve_user_id
+
+try:
+    from _project import resolve_branch, resolve_project_id
+except ImportError:
+    def resolve_project_id() -> str:
+        return os.path.basename(os.getcwd())
+
+    def resolve_branch() -> str:
+        return "unknown"
+
+
+def get_commit_message() -> str:
+    try:
+        result = subprocess.run(
+            ["git", "log", "-1", "--format=%s", "HEAD"],
+            capture_output=True, text=True, timeout=5,
+        )
+        return result.stdout.strip() if result.returncode == 0 else ""
+    except Exception:
+        return ""
+
+
+def get_staged_summary() -> str:
+    try:
+        result = subprocess.run(
+            ["git", "diff", "--cached", "--stat"],
+            capture_output=True, text=True, timeout=10,
+        )
+        return result.stdout.strip() if result.returncode == 0 else ""
+    except Exception:
+        return ""
+
+
+def main() -> int:
+    api_key = resolve_api_key()
+    if not api_key:
+        return 0
+
+    diff_input = sys.stdin.read().strip() if not sys.stdin.isatty() else ""
+    staged = diff_input or get_staged_summary()
+    if not staged or len(staged) < 10:
+        return 0
+
+    user_id = os.environ.get("MEM0_RESOLVED_USER_ID") or resolve_user_id()
+    project_id = os.environ.get("MEM0_PROJECT_ID") or resolve_project_id()
+    branch = os.environ.get("MEM0_BRANCH") or resolve_branch()
+    commit_msg = get_commit_message()
+
+    lines = staged.splitlines()
+    if len(lines) > 30:
+        staged = "\n".join(lines[:30]) + f"\n... ({len(lines) - 30} more lines)"
+
+    content = f"## Commit Context\n\nBranch: {branch}\n"
+    if commit_msg:
+        content += f"Message: {commit_msg}\n"
+    content += f"\n### Staged Changes\n```\n{staged}\n```"
+
+    body = json.dumps({
+        "messages": [{"role": "user", "content": content}],
+        "user_id": user_id,
+        "app_id": project_id,
+        "metadata": {
+            "type": "commit_context",
+            "branch": branch,
+            "source": "pre-commit",
+        },
+        "infer": False,
+    }).encode()
+
+    req = urllib.request.Request(
+        "https://api.mem0.ai/v3/memories/add/",
+        data=body,
+        headers={
+            "Authorization": f"Token {api_key}",
+            "Content-Type": "application/json",
+        },
+        method="POST",
+    )
+
+    try:
+        with urllib.request.urlopen(req, timeout=10):
+            pass
+    except Exception:
+        pass
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())