refactor(openrouter): extract determineFallbackFeature helper

[kilo-code-bot]

Summary

• Extracts a determineFallbackFeature helper in apps/web/src/app/api/openrouter/[...path]/route.ts that decides the fallback value used when no x-kilocode-feature header is provided.
• Drops the legacy /openrouter path check: the URL no longer influences fallback selection.
• The helper returns 'direct-gateway' only when the system prompt does not contain either You are Kilo or You are a personal assistant running inside OpenClaw; otherwise it returns '' so validateFeatureHeader resolves to null.

Verification

N/A (no manual verification performed; no long-running checks run per instructions).

Visual Changes

N/A

Reviewer Notes

• The system-prompt check relies on the 100-char system_prompt_prefix produced by extractPromptInfo. Both marker strings fit comfortably within that prefix, so the check is equivalent to scanning the full system prompt for these well-known opening phrases.
• extractPromptInfo is called twice on this hot path now (once here, once downstream at line ~440). If that becomes a concern we can thread the result through instead.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (1 files)

• apps/web/src/app/api/openrouter/[...path]/route.ts

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_{Reviewed by gpt-5.5-20260423 · 190,979 tokens}

[chrarnoldus]

I see some "You are a personal assistant running inside OpenClaw" and "You are Kilo" as direct-gateway