feat(pr): add Launchpad for pull request management

[CalvinAllen]

Description

Add a Launchpad feature providing a centralized hub for managing pull requests across repositories, with smart organization and actionable insights.

Features

PR Organization Categories

• Ready to Merge - PRs passing all checks, approved
• Blocked - PRs with failing checks or merge conflicts
• Requires Follow-up - PRs needing your attention
• Needs Review - PRs awaiting your review
• Waiting for Review - Your PRs awaiting others' reviews
• Draft - Work-in-progress PRs
• Snoozed - Temporarily hidden PRs

PR Information Display

• PR title and number
• Repository name
• Author with avatar
• Review status and reviewers
• CI/CD check status
• Merge conflict indicator
• Time since last update
• Labels

PR Actions

• Open PR in browser
• Checkout PR branch
• Create worktree for PR
• Merge PR (if permitted)
• Request review
• Approve/Request changes
• Add comments

Organization Features

• Filter by organization/repository
• Pin important PRs
• Snooze PRs temporarily
• Custom grouping options
• Search/filter PRs

Status Bar Integration

• PR count indicator
• Click to open Launchpad
• Color-coded status (action needed, waiting, etc.)
• Customizable indicator format

Polling & Notifications

• Automatic refresh interval
• Desktop notifications for status changes
• Badge updates for new activity

Configuration Options

• Included/excluded repositories
• Included/excluded organizations
• Stale PR threshold (days)
• Refresh interval
• Notification preferences
• Default view/grouping

Dependencies

• feat(integrations): add remote provider integrations #24 - Remote provider integrations (required for PR API access, authentication, and provider support)

Note: This feature requires #24 (Remote provider integrations) to be implemented first, as Launchpad needs authenticated API access to fetch PR data from GitHub, GitLab, Azure DevOps, etc.

Related Issues

• feat(integrations): add remote provider integrations #24 - Remote provider integrations (provides API layer)
• feat(worktrees): add Git Worktrees support #27 - Worktrees (for "Create worktree for PR" action)
• feat(views): add Branches management tool window #22 - Branches management (for branch-related PR actions)

Acceptance Criteria

• PRs are correctly categorized
• All PR information displays accurately
• PR actions execute correctly
• Filtering and search work
• Status bar indicator updates properly
• Notifications fire appropriately