feat: add reactions, bookmarks, polls modules with session remember config

Add three new feature modules (reactions, bookmarks, polls) with corresponding database tables, indexes, and router registrations. Introduce `SESSION_MAX_AGE_REMEMBER` config for extended session duration, add `get_unread_messages` template global, and include operational defaults for rate limiting and session settings in `site_settings`.

tests/conftest.py

@@ -133,6 +133,13 @@ def app_server(test_db_path):
             f"Server did not start after 30s. "
             f"Log:\n{server_log()}"
         )
+
+    from devplacepy.database import get_table as _get_table
+    ops_settings = _get_table("site_settings")
+    for key, value in (("rate_limit_per_minute", "1000000"), ("rate_limit_window_seconds", "60")):
+        if not ops_settings.find_one(key=key):
+            ops_settings.insert({"uid": f"test_{key}", "key": key, "value": value})
+
     yield proc
     try:
         proc.terminate()