feat(desktop): expose OAuth connection accounts

[me2seeks]

Closes #4312

Parent tracking issue: #3852
Follows the Runtime Host OAuth entity binding in #3924.

What changed

• Treat OpenAI Codex and xAI Catalog rows as pure add account connection intents, with 0/1/N configured-connection copy.
• Keep GitHub Copilot as its existing singleton credential-import flow.
• Return and validate the canonical OAuth connectionId + slug + providerType, then navigate to the exact newly created Connection.
• Route Desktop Connection detail and OAuth account operations through immutable connectionId; retain slug only as a checked routing hint and a Desktop-local legacy AppShell seam.
• Separate exact-account logout from Connection deletion and preserve the existing default Connection when adding another account.
• Disambiguate duplicate account names as name · slug, restore focus to the created row on Back, expose live authorization status, and keep adoption/loading failures retryable without reopening the login action.
• Add 0/1/N and duplicate-name stories, plus a regression scenario for the OAuth completion callback versus Host event reload race.

Architecture boundary

This is a Desktop projection/adapter change. Runtime Host remains the canonical OAuth and Connection identity authority. It does not change Runtime Host protocol operations, storage schema, or RUNTIME_HOST_COMPATIBILITY_EPOCH.

UI evidence

Captured from deterministic Storybook fixtures in Chinese at 1440×900. The Before image is from main@28bdbc634; the After images are from this PR head 85f6695e7. Images are pinned to immutable asset commit 3db0ddce3.

Before — provider-wide OAuth state

The Catalog exposes one provider-level email/login state, which makes an existing OAuth account look like the provider's singleton account.

After — add intent and configured Connection counts

OAuth rows are enrollment actions and describe how many Connection entities already exist for that provider.

After — independently addressable accounts

Three same-provider Codex Connections remain distinguishable by name · slug.

After — exact Connection detail

Account state, re-login, logout, model, and Connection actions are presented on the selected immutable Connection entity.

Validation

• Desktop main/preload/renderer/Storybook TypeScript checks
• Desktop renderer architecture checks: 62 passed
• Focused main-process tests: 28 passed
• Preload build
• Renderer production build, entry attestation, and third-party notices check
• git diff --check
• Independent final UI/UX and architecture reviews: GO, no P0-P2 findings

A final Storybook static-build rerun reached the local host filesystem error UNKNOWN: unknown error, write (errno -122). TypeScript Story checks passed, and preload/renderer production builds passed on the exact PR head.

[jackwener]

Reviewed exact head 8a3d3784e154ac9a9b8caa3a1a550e022f41096d. I found no blocking issue.

The production path identifies a connection by immutable connectionId; the slug remains only a checked hint, and both create completion and adoption verify the complete connection identity. The latest commit brings the two Storybook fixtures back into that contract without changing production behavior.

The focused Connection/OAuth and renderer-architecture suites passed 88/88. Exact-head hosted test is successful. Because this branch overlaps current main in four files, I also checked the synthetic merge: Desktop preload, main, renderer, and Storybook typechecks pass on that merge, and the production renderer-architecture check remains green.

---

Automated review notice: This comment was posted by an automated review agent operated by WAWQAQ. It is not an independent human review and does not replace one.