Handle stale settings registry on save

[Hanjo92]

Summary\n- Catch settings save failures so the settings webview no longer remains stuck on Saving....\n- Persist openaiBaseUrl through extension globalState when VS Code's current window still has a stale configuration registry and rejects gitRoast.openaiBaseUrl.\n- Read the fallback value in both the settings panel and runtime roast configuration, so saves work before a window reload.\n- Keep non-fallback configuration update failures visible as webview errors.\n- Clarify stored API key fields: key values remain hidden, blank fields keep saved keys, and pasted values replace them.\n- Add OpenAI request format selection with auto, Responses API, and Chat Completions support for OpenAI-compatible gateways.\n- Improve timeout diagnostics with provider, sanitized URL, model, and timeout budget.\n- Add regression coverage for stale registry fallback behavior, stored API key guidance, and Chat Completions requests.\n- Bump the VSIX build to 0.0.11.\n\n## Verification\n- npx vitest run src/configuration.test.ts src/aiClients.test.ts src/settings/settingsUpdate.test.ts src/settings/settingsHtml.test.ts\n- npm run check\n- npm run package\n- Verified git-roast-0.0.11.vsix contains version 0.0.11, gitRoast.openaiRequestFormat, Chat Completions request code, fallback persistence/runtime code, and visible stored-key guidance.\n- Installed git-roast-0.0.11.vsix locally and verified VS Code reports git-roast.git-roast@0.0.11.\n- Local user settings now explicitly set gitRoast.openaiRequestFormat to chatCompletions for https://llm.vibeprogramminglab.com/v1.\n\nFixes #29\nFixes #31\nFixes #32\nFixes #33