refactor(kilo-auto-model): replace string-keyed maps with zod enums

[kilo-code-bot]

Summary

• Introduced modeSchema (z.enum) for the mode routing keys used in FRONTIER_MODE_TO_MODEL and BALANCED_MODE_TO_MODEL, replacing Record<string, ...> with Record<Mode, ...>
• Introduced legacyModelIdSchema (z.enum) for legacy model IDs, replacing Record<string, AutoModel | undefined> with a fully-typed Record<..., AutoModel>
• All Object.hasOwn(...) guard hacks are eliminated; membership is now checked via z.enum.safeParse()

Verification

• Manual code review; pnpm typecheck could not run in the local environment (tsgo not installed), but the types are straightforwardly correct: Record<Mode, ...> requires all enum members be present (exhaustive), and safeParse returns a discriminated union that narrows the key type.

Visual Changes

N/A

Reviewer Notes

KILO_AUTO_FREE_MODEL_DEPRECATED is now typed as z.infer<typeof legacyModelIdSchema> (i.e. 'kilo/auto' | 'kilo/auto-free') rather than plain string, which is strictly more precise. Callers that compare it with === are unaffected.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (1 files)

• src/lib/kilo-auto-model.ts