Merge remote-tracking branch 'upstream/dev' into improvement-agent-speed

Resolves: surfsense_backend/app/agents/new_chat/middleware/memory_injection.py
- Took both imports: upstream moved MEMORY_HARD_LIMIT/SOFT_LIMIT to
  app.services.memory; kept our perf-logger import for timing.

Pulls in upstream changes:
- Memory document feature (services/memory refactor, removal of
  app.agents.new_chat.memory_extraction and background extraction in
  stream_new_chat — agent now drives memory via update_memory tool).
- BACKEND_URL env refactor across web tool-ui/editor/chat/dashboard/lib.
- GitHub Actions backend test workflow + pre-commit biome bump.
- Token-display polish in MessageInfoDropdown; save_memory no-update
  sentinel.

Verified: 1723 unit tests pass, ruff clean. No semantic regression in
stream_new_chat (their memory-extraction deletion and our preflight
removal touch different functions).

surfsense_backend/app/agents/new_chat/middleware/memory_injection.py

@@ -18,8 +18,8 @@ from langgraph.runtime import Runtime
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from app.agents.new_chat.tools.update_memory import MEMORY_HARD_LIMIT, MEMORY_SOFT_LIMIT
 from app.db import ChatVisibility, SearchSpace, User, shielded_async_session
+from app.services.memory import MEMORY_HARD_LIMIT, MEMORY_SOFT_LIMIT
 from app.utils.perf import get_perf_logger
 
 logger = logging.getLogger(__name__)