fix(desktop): restore accordion expand for credential settings rows

[austinpickett]

What does this PR do?

Restores the collapsible accordion interaction on Provider API Keys and Tools & Keys settings rows. Descriptions, "Get a key" links, and advanced override fields are hidden by default and revealed when a row is clicked or when the key input is focused.

This behavior was removed during the credentials settings polish in #39217; this PR brings it back while keeping the updated ListRow input styling.

Related Issue

Fixes #

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)

Changes Made

• apps/desktop/src/app/settings/credential-key-ui.tsx — Make CredentialKeyCard and ProviderKeyRows collapsible with status dot, chevron, and expanded detail panel
• apps/desktop/src/app/settings/providers-settings.tsx — Track openProvider for single expanded provider row
• apps/desktop/src/app/settings/keys-settings.tsx — Track openKey for single expanded tool/settings row (resets on subnav switch)

How to Test

1. Open Settings → Providers → API keys
2. Confirm rows show only the provider name and key input by default
3. Click a row (e.g. Anthropic) and verify description, "Get a key", and advanced fields expand
4. Open Settings → Tools & Keys → Tools (and Settings)
5. Confirm the same accordion behavior for tool and server credential rows

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: Linux (WSL2)

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — or N/A
• I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A
• I've updated tool descriptions/schemas if I changed tool behavior — or N/A

Screenshots / Logs

[github-actions]

🔎 Lint report: austin/fix/get-keys vs origin/main

ruff

Total: 0 on HEAD, 0 on base (➖ 0)

🆕 New issues: none

✅ Fixed issues: none

Unchanged: 0 pre-existing issues carried over.

ty (type checker)

Total: 9840 on HEAD, 9840 on base (➖ 0)

🆕 New issues: none

✅ Fixed issues: none

Unchanged: 5102 pre-existing issues carried over.

Diagnostics are surfaced as warnings — this check never fails the build.