[Gemini Log Analyzer] Part 4: Frontend Integration (Dashboard UI)

[ievdokdm]

This is Part 4 of the stacked Pull Request series implementing the Gemini Log Analyzer feature.

Depends on Part 3: #5043 (Note: Targets main due to GitHub cross-repo limits, but chains to #5043 via description).

This PR integrates the feature into the Cocoon Dashboard UI:

• Adds "Log Analysis" tab to display the Gemini log analyzer results when available.
• Adds "Analyze Logs with Gemini" action button to trigger the API from the presubmit dashboard.
• Implements spellchecking, permission-checking, and error-handling for the trigger action.

Stacked PR Series:

• Part 1: Backend Foundation (Models & Setup) (Merged)
• Part 2: Backend Infrastructure (Config & Database Data Flow) ([Gemini Log Analyzer] Part 2: Backend Infrastructure (Config, Models, & Database Flow) #5045)
• Part 3: Backend Core API (Genkit Logic & Handlers) ([Gemini Log Analyzer] Part 3: Backend Core (Analyze Logs API & Service) #5043)
• Part 4: Frontend Dashboard UI (This PR)