fix(dashboard): align web session memory paths with chat history

[cursor]

Summary

Fixes a critical data-path mismatch where Dashboard chat writes conversation memory to data/memory/dashboard/<user>/ while the UI reads history from data/memory/web/<user>/.

Bug and impact

• Impact: Dashboard users appear to lose chat history on refresh; new turns are persisted under the wrong memory namespace and never show up in /chat/history.
• Root cause: chat() / chat_stream() passed metadata={"source": "dashboard"}, which overrode the IPC gateway's source=web via setdefault semantics. _daemon_chat_db_path() resolves history from the web: session prefix.
• Secondary: CLI /session switch to web:<user> left acquire owner as cli:root because _resolve_core_owner did not include web: sessions.

Fix

• Remove the dashboard metadata source override from chat endpoints.
• Always use source=web in _with_client() so IPC and session IDs align.
• Extend _resolve_core_owner to remap web: sessions when callers pass CLI defaults.

Validation

• tests/test_core_owner_resolve.py (web session owner resolve)
• tests/test_kernel_runtime.py::test_dashboard_web_session_memory_owner_matches_history_path