fix(api): require HTTPS for custom Google Gemini base URLs (CWE-319) (#2033)

* fix(api): require HTTPS for custom Google Gemini base URLs (CWE-319)

googleGeminiBaseUrl is user-editable (settings, imported profiles) and the
@google/genai client keeps API-key authentication for custom endpoints, so a
cleartext base URL would send the API key over an insecure endpoint (CWE-319).

Validate the endpoint before any request in createMessage and completePrompt:
HTTPS is required; plain HTTP is accepted only for loopback test proxies
(localhost, [::1], and literal 127.0.0.0/8 IPv4 hosts). Hostnames that merely
resemble the loopback range (127.example.test, 127.0.0.a, 127.0.0.1.a,
foo127.bar) or fall outside it (10.0.0.1) are rejected, as are non-HTTP
schemes such as ftp://localhost and malformed URLs. Violations surface as a
structured ApiProviderError before the request is built, so the key never
leaves the process.

Carved out of the abort-signal provider rollout (fork PR 1303) at the
maintainer's request so the endpoint policy can be reviewed independently of
the cancellation changes.

* chore(lint): limit Stryker directive comments to 300 characters

* test(api): cover Gemini HTTPS accept path and completePrompt rejects

* docs(agents): require accept and reject tests for guards

---------

Co-authored-by: Eason Liang <easonliang28@gmail.com>
Co-authored-by: Elliott de Launay <edelauna@gmail.com>

Author: 3 people

.coderabbit.yaml

@@ -79,6 +79,9 @@ reviews:
               Require regression coverage at the lowest valid harness with behavior-focused
               assertions, including relevant negative, error, false/unset, and boundary cases.
               Check cleanup and deterministic async behavior and prefer shared typed test helpers.
+              For guards and validators, require tests for both the accept path and the reject path
+              through every public entry point; a reject-only matrix cannot catch a guard that rejects
+              good input.
               Visible webview changes require a durable Playwright component snapshot; behavior-only
               changes do not.
               Reject weak assertions on values that could take multiple forms: .toBeDefined() or

AGENTS.md

@@ -54,6 +54,9 @@ Prefer the narrowest test layer that proves the behavior. This follows standard
 - Use `apps/vscode-e2e` only when the behavior depends on the real VS Code extension host, VS Code workspace APIs, extension activation, webview/extension messaging, file watcher behavior, or a complete user workflow.
 - Keep e2e tests focused on high-value smoke coverage across boundaries. Avoid placing detailed protocol, parsing, storage, retry, or edge-case assertions in e2e when they can be covered reliably at a lower layer.
 - When fixing a regression, add the regression test at the lowest layer that would have failed for the bug. Add an e2e test only if lower-level tests cannot represent the failure mode.
+- For a guard or validator, test the accept path and the reject path through every public entry point. A test that only rejects bad input does not prove the guard still accepts good input.
+- Use `it.each` for repeated cases and share the setup in a helper. Do not copy a test body per input.
+- A `Stryker disable` comment states the reason in one sentence. ESLint `max-len` limits it to 300 characters.
 
 ## Task Lifecycle Changes