[SSR Agent] Issue Fix (339): Connect pre-installed companion extension without reinstallation

[joneba-google]

fixes #339

Context & Problem

The Gemini CLI unconditionally attempts to run /ide install when connection
prompts are accepted, even if the IDE companion extension is already
pre-configured or running. This results in installation errors when the
integration is already available. This is caused by handleIdePromptComplete in
packages/cli/src/ui/AppContainer.tsx ignoring isExtensionPreInstalled from
the nudge completion results.

Detailed Changes

• Updated handleIdePromptComplete in packages/cli/src/ui/AppContainer.tsx to
  branch based on result.isExtensionPreInstalled. If true, /ide enable is
  run; otherwise, /ide install is executed.
• Added a new unit test in packages/cli/src/ui/IdeIntegrationNudge.test.tsx to
  verify isExtensionPreInstalled is set correctly on dismiss selections when
  pre-installed environments are set.

Verification

• Verified lint results in linter_output.txt showed that the checks succeeded.

[github-actions]

📊 PR Size: size/S

• Lines changed: 36
• Additions: +35
• Deletions: -1
• Files changed: 2