Task: Integrate unified plugin workspace into client main

Identity

Fast-forward client main from exact base e9875145b41a2cb1827de10d27a4fc6a352704ea through the approved unified Plugin workspace design and reviewed product head d7058e6383f1e9dd72c32570cf83b9f439d91033.
Promote only the accepted Integration-Gate memory changes: record the unified /plugins surface in current state and replace the stale three-page entry in the architecture module map.
Preserve the three pre-existing untracked task records in the client root exactly; do not stash, reset, clean, delete, move, or adopt them.
Run bounded integration verification, complete the task documentation gate, and release the root integration lock.

The fixed product range is 959e2faf03dfacb3c8e2035e44774436c752d4b0...d7058e6383f1e9dd72c32570cf83b9f439d91033. R4 task 20260903-plugin-navigation-acceptance-r4-9c2f6a41 independently passed Standards and Spec with zero findings.
Preserve the existing Catalog, Account Library, official Package Store, Device Package, project enablement, Agent assignment, runtime admission, and billing authorities. This integration changes only the already-reviewed Renderer product and canonical project memory.
Keep local Skill/extension installation conversation-only and keep selected-model native Web Search outside the Plugin projection.
Related task 20260903-design-message-send-client-8d3f2a71 is Ready for Integration and explicitly excludes Plugin pages, navigation, Sidebar, and router code; no semantic or file ownership conflict exists.
Do not push, open a PR, deploy, publish, package, or install a client.

Startup memory, integrated current state, decisions, system overview, module map, data flow, business rules, success criteria, glossary, evidence, commitments, and stale-item registry were read from the exact client base.
The approved ML-PLUGIN-NAV-001 specification and the implementation, three remediation, and final R4 acceptance records were read in full.
main at e9875145b41a2cb1827de10d27a4fc6a352704ea is an exact ancestor of the reviewed product head, so the product integration is eligible for --ff-only.
Concurrent Task Gate: Passed. Planning Gate: Passed.

Fast-forwarded local client main from e9875145b41a2cb1827de10d27a4fc6a352704ea to the exact reviewed product head d7058e6383f1e9dd72c32570cf83b9f439d91033; no merge conflict or product rewrite occurred.
The canonical Code Plugin surface is now one sidebar entry and one /plugins workspace. The three old routes remain replace-only redirects and the deleted old page implementations do not remain as fallbacks.
Promoted the implementation task's architecture candidate into module-map.md, recorded the integrated product and R4 evidence in current-state.md, and corrected the obsolete My Plugins wording in the durable Device Package rule.
Preserved all three pre-existing untracked client-root task records exactly. No push, PR, deployment, publication, package, or user-machine installation occurred.

Pre-integration ancestry check proved the root base is an ancestor of the reviewed product head; git merge --ff-only advanced through exactly five commits (approved design plus implementation and three remediations).
Final R4 acceptance record reports Standards PASS and Spec PASS with zero findings over 959e2faf03dfacb3c8e2035e44774436c752d4b0...d7058e6383f1e9dd72c32570cf83b9f439d91033.
Post-merge focused verification passed: 8 files / 83 tests.
Post-merge corepack pnpm run typecheck passed.
Source evidence retained by R4: full unit 1842 passed / 2 skipped plus pressure 1 passed; lint 0 errors with 5 pre-existing warnings; all Vite targets passed; targeted Electron Plugin E2E passed 4/4.
check_project_docs, staged diff check, exact branch/HEAD, focused tests, and typecheck passed. The task-aware drift script now reports only the three pre-existing untracked foreign task records; they predate this integration and were deliberately left unchanged, but the script has no pre-existing-path exemption.

Closing the task documentation gate and releasing the dirty-root integration lock requires explicit handling authorization for the three preserved foreign task records; they must not be deleted, adopted, or permanently moved.
A rebuilt and installed client smoke remains a separate release activity; it was not authorized or required by this source integration.