Add immutable memory index snapshots (#1022)

* feat: add immutable memory index snapshots

Capture the visible memory metadata index at first model admission, preserve it as immutable system-prefix context, and emit relevance pointers without rewriting cached history. Align project authorization, MCP actor refresh ordering, storage APIs, SDKs, console surfaces, and regression coverage with the snapshot lifecycle.

* fix: stabilize memory index for release candidate

* fix(sdk): avoid polynomial description trim

* chore: split memory index documentation

scripts/recovery_e2e.py

@@ -1598,6 +1598,7 @@ def _launch_chrome(chrome: str, profile: Path) -> tuple[subprocess.Popen[bytes],
             "--disable-gpu",
             "--no-sandbox",
             "--no-first-run",
+            "--password-store=basic",
             "--disable-extensions",
             "--disable-background-timer-throttling",
             f"--remote-debugging-port={cdp_port}",