feat(seo): account-management verbs (connect/accounts/forget) + connect.sh wrapper

tokenstore remove/clear, fetch.sh forget dispatch, and a connect.sh wrapper
that sources ~/.claude/.env internally and runs from any project. /seo now
routes connect|accounts|forget before the audit flow; Makefile seo-connect
delegates to the wrapper. Labels are guarded to shell-safe ASCII (POSIX case,
whole-string, C-locale) as defense-in-depth; forget output states local
removal is not a Google-side revocation.

lib/seo-data/tokenstore.py

@@ -2,6 +2,7 @@
 """Label-keyed OAuth refresh-token store. Atomic writes under an fcntl lock.
 No third-party deps — must run without the venv (used by the offline test path)."""
 import argparse, fcntl, json, os, tempfile
+from contextlib import contextmanager
 from datetime import datetime, timezone
 
 def load(path):
@@ -21,14 +22,34 @@ def list_accounts(path):
 def get_refresh_token(path, label):
     return load(path).get("accounts", {}).get(label, {}).get("refresh_token")
 
+@contextmanager
+def _locked(path):
+    """Exclusive fcntl lock around a store mutation (serializes writers)."""
+    lock_path = path + ".lock"
+    with open(lock_path, "w") as lock:
+        os.chmod(lock_path, 0o600)                 # defense-in-depth (empty flock handle, never holds token)
+        fcntl.flock(lock, fcntl.LOCK_EX)
+        yield
+
+def _atomic_write(path, data):
+    """tmp → fsync → chmod 0600 → atomic rename, in the store's directory."""
+    dirpath = os.path.dirname(path) or "."
+    fd, tmp = tempfile.mkstemp(dir=dirpath, suffix=".tmp")
+    try:
+        with os.fdopen(fd, "w", encoding="utf-8") as f:
+            json.dump(data, f, indent=2)
+            f.flush(); os.fsync(f.fileno())
+        os.chmod(tmp, 0o600)
+        os.replace(tmp, path)                     # atomic
+    finally:
+        if os.path.exists(tmp):
+            os.unlink(tmp)
+
 def save_account(path, label, refresh_token, scopes, properties):
     dirpath = os.path.dirname(path) or "."
     os.makedirs(dirpath, mode=0o700, exist_ok=True)
     os.chmod(dirpath, 0o700)                       # re-assert invariant (makedirs no-ops if dir exists)
-    lock_path = path + ".lock"
-    with open(lock_path, "w") as lock:
-        os.chmod(lock_path, 0o600)                 # defense-in-depth (empty flock handle, never holds token)
-        fcntl.flock(lock, fcntl.LOCK_EX)          # serialize concurrent connects
+    with _locked(path):
         data = load(path)
         data.setdefault("version", 1)
         data.setdefault("accounts", {})
@@ -38,16 +59,28 @@ def save_account(path, label, refresh_token, scopes, properties):
             "granted_at": datetime.now(timezone.utc).isoformat(),
             "properties": properties,
         }
-        fd, tmp = tempfile.mkstemp(dir=dirpath, suffix=".tmp")
-        try:
-            with os.fdopen(fd, "w", encoding="utf-8") as f:
-                json.dump(data, f, indent=2)
-                f.flush(); os.fsync(f.fileno())
-            os.chmod(tmp, 0o600)
-            os.replace(tmp, path)                 # atomic
-        finally:
-            if os.path.exists(tmp):
-                os.unlink(tmp)
+        _atomic_write(path, data)
+
+def remove_account(path, label):
+    """Drop one label from the store. Returns True if it existed."""
+    if not os.path.exists(path):
+        return False
+    with _locked(path):
+        data = load(path)
+        existed = data.get("accounts", {}).pop(label, None) is not None
+        if existed:
+            _atomic_write(path, data)
+    return existed
+
+def clear_accounts(path):
+    """Empty the store (file and perms kept). Returns removed count."""
+    if not os.path.exists(path):
+        return 0
+    with _locked(path):
+        data = load(path)
+        count = len(data.get("accounts", {}))
+        _atomic_write(path, {"version": 1, "accounts": {}})
+    return count
 
 def _cli():
     p = argparse.ArgumentParser()
@@ -58,10 +91,20 @@ def _cli():
         ps.add_argument(flag, required=True)
     ps.add_argument("--scopes", default="")
     ps.add_argument("--properties", default="")
+    pr = sub.add_parser("remove")
+    for flag in ("--file", "--label"):
+        pr.add_argument(flag, required=True)
+    pc = sub.add_parser("clear"); pc.add_argument("--file", required=True)
     try:
         args = p.parse_args()
         if args.cmd == "list":
             print(json.dumps({"status": "ok", "accounts": list_accounts(args.file)}))
+        elif args.cmd == "remove":
+            print(json.dumps({"status": "ok",
+                              "removed": remove_account(args.file, args.label)}))
+        elif args.cmd == "clear":
+            print(json.dumps({"status": "ok",
+                              "cleared": clear_accounts(args.file)}))
         else:
             save_account(args.file, args.label, getattr(args, "refresh_token"),
                          [s for s in args.scopes.split(",") if s],