[Fix] Reasoning label changes when users move the DeepSeek picker

[roomote-roomote]

​Created by Roomote. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

What changed

• Keep model-picker chips, slider indices, and reasoning labels on one capability-aware selection. DeepSeek V4.1 Flash consistently shows Low / High / Max, including when a saved default or explicit override is medium.
• Share V4.1 Flash compatibility-alias resolution between settings/presets and OpenCode provider options: medium and xhigh request High, matching DeepSeek's documented mapping. Cover current and retained Vercel/OpenCode Go route aliases, and carry the underlying model ID through Same as coding model options.
• Preserve saved defaults and inheritance when viewing the picker or clicking the selected model. An explicit slider change saves its canonical level. Update the model documentation and add regressions for the reported sequence, legacy overrides, supported-stop ordering, and provider option shapes.

Why this change was made

The session chip displayed the raw configured medium, while the slider used the model's published ['low', 'high', 'max'] stops. An unsupported inherited default fell back to the middle stop (High); returning there after a slider change emitted high, changing the chip's label. An explicit legacy medium took a separate nearest-level path that could even display Low on a distance tie. The provider already maps Medium to High, so inventing a distinct Medium stop would misrepresent the model.

Impact

Selection	Saved value after this change	Display / provider effort
Inherit a deployment medium default	Deployment stays medium; session stays inherited	High / explicit high provider option
Existing explicit medium override	Remains medium until edited	High / explicit high provider option
Choose Low, then return to the middle	Explicit high override	High / high
Choose Max	Explicit max override	Max / max

Other model defaults and existing fallback selection policy remain unchanged; no database migration or automatic rewrite of saved choices is needed.

The new session regression failed on the original code (chip read DeepSeek V4.1 FlashMedium) and passes with the fix. Targeted web/settings/catalog/session-command tests passed (160 tests), as did targeted types/provider/config tests (153 tests); the affected picker/settings suites were rerun after the final adjustment (84 tests). pnpm lint:fast, pnpm check-types:fast, pnpm knip, and the commit/push hooks passed. mise exec -- pnpm --filter @roomote/docs check passed, and the updated docs page rendered in the local preview.

Browser proof capture exceeded its shared deadline (proof capture timed out); no visual proof is included. Provider-effective effort is grounded in official documentation and provider-option regression checks; no live billable model generation was sampled.

[roomote-community]

No code issues found. See task

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