feat: add kimi and minimax oauth login (#291)

## Related Issue

No tracking issue — maintainer-directed change in the repository owner's
branch.

## Problem

Two independent gaps:

1. The login flow only offered API-key platforms and OpenAI Codex OAuth.
Kimi For Coding and MiniMax (global and China) subscriptions could not
be connected from pythinker-code.
2. OpenCode Go requires the `x-opencode-session` header (one stable id
per conversation) on gateway requests; pythinker-code did not send it.
OpenCode billing rejections such as `401 Insufficient balance` were also
being mislabeled as authentication failures.

## What changed

- Added Kimi For Coding and MiniMax OAuth sign-in for global and China
regions.
- Kimi now uses the official device flow, stable device identity
headers, sanitized host OS release, persisted OAuth credentials,
refresh-token rotation, and restart-safe runtime refresh.
- MiniMax now follows the official MiniMax CLI PKCE/state device flow,
including `user_code`, millisecond `expired_in`, provider-specific
polling semantics, persisted OAuth credentials, refresh-token rotation,
and regional endpoints.
- OAuth bearer tokens and refresh tokens are no longer embedded in
`config.toml`; providers reference the existing credential store
instead.
- Runtime OAuth refresh uses a five-minute proactive refresh window,
forced refresh after authorization failure, single-flight refresh for
concurrent requests, and persistence of rotated credentials.
- Device authorization cancellation now aborts the initial request and
cannot open a browser after cancellation. Kimi/MiniMax cancellation
during model selection/config loading resolves the login flow as `false`
without committing config.
- `scripts/check-product-boundaries.mjs`: the hosted-inference-endpoint
guard exempts `packages/oauth/src/kimi-oauth.ts` via the existing allow
mechanism because the direct device-OAuth login legitimately targets
that upstream; every other surface stays banned.
- Model requests to HTTPS OpenCode gateway hosts (`opencode.ai` and
subdomains) send `x-opencode-session` with a stable conversation id.
HTTP and lookalike hosts receive no session header. The one-shot
connectivity probe generates a fresh UUID for every probe.
- OpenCode `401 Insufficient balance` responses are classified as
provider/billing failures rather than `provider.auth_error`; ordinary
invalid-credential 401 responses remain authentication errors.
- Added focused regression coverage for OAuth protocol behavior,
refresh/rotation, cancellation, credential references, OpenCode billing
classification, HTTPS-only session headers, and fresh ping session IDs.
- Changesets are included for the user-facing changes.

## Checklist

- [x] I have read the
[CONTRIBUTING](https://github.com/PyModel/pythinker-code/blob/main/CONTRIBUTING.md)
document.
- [x] No related issue is required for this maintainer-directed change.
- [x] I have added tests that prove the feature and fixes work.
- [x] Ran `gen-changesets` skill, or this PR needs no additional
changeset.
- [x] Ran `gen-docs` skill, or this PR needs no doc update.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added OAuth sign-in for Kimi For Coding and MiniMax in global and
China regions.
* Added device-code authentication, model selection, cancellation, and
account configuration.
  * Added per-conversation session support for OpenCode Go requests.
  * Added custom request-header support across supported AI providers.
  * Added a workspace endpoint for adding directories.

* **Bug Fixes**
* Improved OAuth refresh reliability, concurrency protection, timeouts,
and credential preservation.
  * Improved browser sign-in fallback and Windows Codex login.
  * Improved authentication, billing, and quota error handling.
  * Updated permission-mode labels and trust-prompt defaults.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: elkaix

.agents/skills/agent-core-review/slop/SKILL.md

@@ -24,7 +24,7 @@ Severity grades, merge/block verdicts, and "is splitting worth it" calls live do
 
 ## When to use
 
-Apply this lens only when the user asks for it explicitly (for example "用单一抽象层次审视一下", "check whether this function does too much", "errors should be handled above/below, right?"). Leave general reviews and refactors to other lenses unless the user names this one.
+Apply this lens only when the user asks for it explicitly (for example "review the levels of abstraction", "check whether this function does too much", "errors should be handled above/below, right?"). Leave general reviews and refactors to other lenses unless the user names this one.
 
 ## The principle
 

.agents/skills/write-tui/DESIGN.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": minor
+---
+
+Add OAuth sign-in for Kimi For Coding and MiniMax (global and China) to the login flow.

.changeset/kimi-minimax-oauth-login.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Keep the stored refresh token when a provider refresh response omits a replacement.

.changeset/kimi-refresh-token.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Stop blocking dangerous Bash commands in Never Ask mode.

.changeset/never-ask-guard.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Prevent concurrent sessions from overwriting each other's refreshed sign-in tokens.

.changeset/oauth-refresh-locking.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Bound OAuth refresh requests with a timeout and reject tokens that arrive after expiry.

.changeset/oauth-refresh-timeouts.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Send OpenCode Go requests with a per-conversation session header.

.changeset/opencode-session-header.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Rename the permission modes to Always Ask, Ask When Needed, and Never Ask, and open the mode list for /yolo and /auto.

.changeset/permission-mode-names.md

@@ -0,0 +1,5 @@
+---
+"@pymodel/pythinker-code": patch
+---
+
+Default the workspace trust prompt to Trust this folder and require Enter to confirm.