[SSR Agent] Issue Fix (346): Fix IDE integration using pre-installed extension

[joneba-google]

fixes #346

Context & Problem

When a user accepts the IDE integration prompt in VS Code while the companion
extension is already installed/running, Gemini CLI unconditionally executes
/ide install rather than enabling the existing connection via /ide enable.
This occurred because the handleIdePromptComplete callback inside
AppContainer.tsx ignored the isExtensionPreInstalled flag returned by
IdeIntegrationNudge and hardcoded /ide install.

Detailed Changes

• packages/cli/src/ui/AppContainer.tsx: Updated handleIdePromptComplete to
  inspect result.isExtensionPreInstalled when the user selection is 'yes'.
  It now appropriately triggers /ide enable when pre-installed, or falls back
  to /ide install otherwise.
• packages/cli/src/ui/AppContainer.test.tsx: Added comprehensive unit tests
  evaluating both branches (isExtensionPreInstalled as true and false) to
  verify that the correct slash commands are processed.

Verification

The logic was statically verified and validated via the updated test suite in
packages/cli/src/ui/AppContainer.test.tsx.

GitHub Issue: #346

[github-actions]

📊 PR Size: size/M

• Lines changed: 54
• Additions: +52
• Deletions: -2
• Files changed: 2