Member invites, gallery resync, content and operator docs

- Invite flow: admin issue/revoke on join requests, public single-use
  claim links (hash-only tokens, 7-day expiry, no state reveal), claim
  creates the Member account and marks the request accepted
- Gallery: admin status page plus resync endpoint; sync refreshes
  thumbnails whose content changed; tools/gallery contract and checker
- Docs: public content page, admin-only operator runbook, api.md
  invite/gallery sections, all routes in the live API docs, docs
  reachability gate test
- Screenshots cover the new pages; version 1.0.18

molodetz/database/init_db.py

@@ -67,6 +67,20 @@ TABLE_EXAMPLES = {
         "deleted_at": None,
         "deleted_by": None,
     },
+    "member_invites": {
+        "uid": "x",
+        "token_hash": "x",
+        "join_request_uid": "x",
+        "email": "",
+        "username": "",
+        "created_by": "x",
+        "created_at": now_iso(),
+        "expires_at": now_iso(),
+        "used_at": None,
+        "used_by": None,
+        "revoked_at": None,
+        "revoked_by": None,
+    },
     "media_items": {
         "uid": "x",
         "filename": "x.jpg",
@@ -200,6 +214,9 @@ def init_db():
     _index("CREATE INDEX IF NOT EXISTS idx_posts_author ON posts(user_uid, created_at)")
     _index("CREATE INDEX IF NOT EXISTS idx_posts_trash ON posts(deleted_at) WHERE deleted_at IS NOT NULL")
 
+    _index("CREATE UNIQUE INDEX IF NOT EXISTS idx_member_invites_uid ON member_invites(uid)")
+    _index("CREATE UNIQUE INDEX IF NOT EXISTS idx_member_invites_token ON member_invites(token_hash)")
+    _index("CREATE INDEX IF NOT EXISTS idx_member_invites_join ON member_invites(join_request_uid, created_at)")
     _index("CREATE UNIQUE INDEX IF NOT EXISTS idx_join_requests_uid ON join_requests(uid)")
     _index("CREATE INDEX IF NOT EXISTS idx_join_requests_status ON join_requests(status, created_at)")
     _index("CREATE INDEX IF NOT EXISTS idx_join_requests_trash ON join_requests(deleted_at) WHERE deleted_at IS NOT NULL")