fix(init): normalize custom base URL

[Kushagra963-lab]

Closes #109

Summary

• Trim trailing slashes from custom OpenAI-compatible base URLs before saving config.
• Keep existing URL validation behavior unchanged.
• Add regression coverage for normalized and unchanged custom base URLs.

Testing

• Not run locally; GitHub clone/test access timed out in this environment.

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PR Review: fix(init): normalize custom base URL

Overview

Criterion	Assessment
Purpose	✅ Clear — trims trailing slashes from custom base URLs before saving to config, closing #109
Scope	✅ Focused — one small normalization fix + regression test
Size	✅ Minimal (21 lines changed)

Correctness & Logic

The new normalizeBaseUrl function strips one or more trailing slashes from user-supplied URLs before they're persisted to config — correct and well-targeted.

All three provider adapters already strip trailing slashes at request time (openai-compatible.ts:8, anthropic.ts:8, cohere.ts:8), so this doesn't change runtime behavior — but it does normalize the saved config, which is the right thing to do. Users shouldn't see a trailing-slash URL in their persisted config when it will always be used without one.

Edge cases are fine: the URL validate callback rejects empty/invalid URLs before normalizeBaseUrl is reached, and the regex \/+ correctly handles one or more trailing slashes.

Code Quality & Maintainability

• Readability: ✅ Clean, self-explanatory function name and implementation.
• Exports: ✅ Exported for testability, consistent with how buildApiKeyPrompt is exported.
• Conventions: ✅ Matches project style (minimal, no unnecessary comments).

Security

✅ No concerns. Simple regex replacement, no new dependencies, no secrets exposed.

Testing

The new tests/init-base-url.test.mjs follows project conventions (node:assert/strict + node:test, imports from ../dist/). Coverage is reasonable with trimming and passthrough cases.

However, two issues need attention before merge:

1. Tests were not run by the author. The PR description states "Not run locally; GitHub clone/test access timed out." Please confirm CI passes or run npm run build && node --test tests/init-base-url.test.mjs locally before merge.

2. Missing edge case: The tests cover multi-trailing-slash (v1///) and no trailing slash (v1), but don't explicitly test the most common scenario — a single trailing slash (v1/). While the regex handles it, this is the exact case the PR claims to fix and should have explicit coverage:

test('handles single trailing slash', () => {
  assert.equal(normalizeBaseUrl('https://api.example.com/v1/'), 'https://api.example.com/v1');
});

Breaking Changes

✅ None.

Documentation

The PR description could mention this is a config-level normalization (not a behavior change), since the providers already handled trailing slashes at request time.

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Verdict: Request changes

The implementation is correct and clean, but the single-trailing-slash edge case (the exact scenario from #109) is not explicitly tested, and the tests haven't been verified to pass. Please add the missing test case and confirm tests pass.