feat: add Claude CLI OAuth support for subscription accounts

[wade56754]

Summary

• Add a new "Claude CLI (Subscription)" provider preset that allows Pro/Max/Team subscription users to use CodePilot without an API key
• Leverages Claude CLI's built-in OAuth tokens stored in ~/.claude/ — users just need to run claude login first
• New cli_oauth auth style clears all ANTHROPIC_* env vars so the Claude CLI subprocess falls back to its own OAuth flow

Problem

Currently CodePilot requires either an API key or a third-party provider configuration. Users with Anthropic Pro/Max/Team subscriptions who have already authenticated via claude login cannot use their subscription — they get "Claude Code process exited with error" because no credentials are injected.

Changes

File	Change
provider-catalog.ts	New cli_oauth AuthStyle + vendor preset definition
provider-resolver.ts	toClaudeCodeEnv() cli_oauth branch: clears ANTHROPIC_* vars, lets CLI use own OAuth
provider-resolver.ts	hasCredentials returns true for cli_oauth
provider-resolver.ts	inferAuthStyleFromProvider reads __AUTH_STYLE marker from env_overrides
provider-presets.tsx	New "Claude CLI (Subscription)" quick-add button (first position)
PresetConnectDialog.tsx	Injects __AUTH_STYLE marker for cli-oauth preset

How it works

1. User clicks "Claude CLI (Subscription)" in provider settings — no fields to fill, just Connect
2. Provider record created with empty api_key, empty base_url, env_overrides_json: {"__AUTH_STYLE":"cli_oauth"}
3. When spawning Claude Code subprocess, toClaudeCodeEnv() detects cli_oauth → clears all ANTHROPIC_* env vars
4. Claude CLI finds no API key → uses its own OAuth tokens from ~/.claude/

Test plan

• npm run typecheck — passes
• npm run test:unit — 374 tests pass, 0 fail (including 82 provider-resolver tests)
• Manual test: select "Claude CLI (Subscription)", verify Claude Code uses OAuth auth
• Manual test: switch between CLI OAuth and API key providers, verify no credential leaks

🤖 Generated with Claude Code

[vercel]

Someone is attempting to deploy a commit to the op7418's projects Team on Vercel.

A member of the Team first needs to authorize it.