Greptile Summary

This PR eliminates a redundant structuredClone on the skipCache: true path of loadSessionStore. When callers pass skipCache: true (e.g., updateSessionStore, updateSessionStoreEntry) they force a fresh disk read and intend to mutate the result before saving — cloning was wasteful because the parsed store object is never placed into the shared object cache on that code path.

• src/config/sessions/store.ts: Adds an early return of the raw parsed store when opts.skipCache is true, bypassing the defensive structuredClone that was protecting callers only from a shared cache reference (which doesn't exist on this path).
• src/config/sessions/store-cache.ts (read for context): writeSessionStoreCache already clones internally via structuredClone(params.store), and it is skipped entirely when skipCache: true, confirming the cache is never aliased to the returned object.
• src/config/sessions.test.ts: Adds a regression test verifying that mutating the value returned from skipCache: true does not taint subsequent cached or uncached reads.

Confidence Score: 5/5

Safe to merge — the optimization is logically sound, no shared object aliases are possible on the skipCache path, and the new regression test covers the key invariant.

The invariant is solid: writeSessionStoreCache (which is the only way a store object enters the shared cache) is explicitly skipped when opts.skipCache is true. The freshly-parsed store is therefore never aliased into the cache, so returning it directly cannot taint any subsequent reads. Both primary call-sites (updateSessionStore, updateSessionStoreEntry) hold a write lock, mutate the returned store intentionally, and then save — exactly the pattern the optimization is designed for. No P1 or P0 issues found.

No files require special attention.

_{Reviews (1): Last reviewed commit: "Avoid redundant cloning on fresh session..." | Re-trigger Greptile}

The remaining CI failures are pre-existing issues unrelated to this PR:

• extension-fast (whatsapp) and checks-node-channels-3: same test failing — extensions/whatsapp/src/action-runtime.test.ts > applies default account allowFrom when accountId is omitted (ToolAuthorizationError assertion mismatch). This PR only touches src/config/sessions/.
• macos-swift: Swift formatting lint failure on a file this PR does not modify.

The original checks-windows-node-test-5 timeout was also a pre-existing flaky runner issue — it passed in 4m51s on the rerun today.

Superseded by #60595. Closing this older broader variant in favor of the latest clean 2-file session-store PR on top of the latest main.