feat(openrouter): configurable base URL with OPENROUTER_BASE_URL env override

[cryptoxdog]

Summary

Makes the OpenRouter base URL configurable instead of hardcoded, using the standard OpenAI-compatible pattern: explicit config takes precedence, then the OPENROUTER_BASE_URL environment variable, then the built-in default. This unblocks routing through proxies, gateways, and regional endpoints without touching provider code.

Verification: tsc build clean, ESLint clean, Vitest 17 files / 88 tests pass (12 new).

Problem

src/providers/openrouter.ts constructed its transport with a hardcoded baseURL: 'https://openrouter.ai/api/v1'. During the Website-Bot go-live run this surfaced as a defect: any deployment that needs to reach OpenRouter through a proxy or an OpenAI-compatible gateway had no supported way to redirect traffic — the only options were forking the provider or monkey-patching the transport.

Changes

• src/providers/openrouter.ts
  • New exported DEFAULT_OPENROUTER_BASE_URL constant and InvalidBaseUrlError typed error.
  • New resolveOpenRouterBaseUrl(configured?, env = process.env):
    • Precedence: explicit config → OPENROUTER_BASE_URL env var → default.
    • Trims whitespace, strips trailing slashes, validates the value parses as an absolute http(s) URL; anything else throws InvalidBaseUrlError (fail-fast at construction, not first request).
  • OpenRouterClient constructor accepts baseUrl as a new trailing optional parameter — fully backward compatible with all existing call sites.
• src/types.ts — RouterConfig.openrouterBaseUrl (optional, documented).
• src/schemas.ts — RouterConfigSchema.openrouterBaseUrl: Zod url() plus an http(s)-scheme refine.
• src/index.ts — router wires validated.openrouterBaseUrl through to the client; new symbols re-exported.
• README.md — new "Custom OpenRouter endpoint" section documenting both configuration paths and precedence.

Tests (12 new, tests/openrouter-base-url.test.ts)

• Default resolution when nothing is configured.
• Config value wins over env; env wins over default (full precedence matrix).
• Trailing-slash and whitespace normalization.
• Rejection of invalid values: empty string, non-URL, ftp://, missing scheme.
• Constructor integration: client transport receives the resolved URL.
• Schema-level validation of openrouterBaseUrl in RouterConfig.

How to verify

npm run build && npm run lint && npm test
OPENROUTER_BASE_URL=https://my-gateway.example.com/api/v1 node -e "…"  # env override

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud