[User Story] As a user, I want `git-copilot review` to analyse my current branch and display findings in the terminal

[coderabbitai]

User Story

As a developer before a pull request,
I want to run git-copilot review and see security, performance, and code-quality findings in my terminal,
So that I can fix issues before requesting review from teammates.

Acceptance Criteria

• Runs the 6 agents (security, performance, architecture, code-quality, dependency, git-history) in parallel
• Shows a live progress dashboard (agents running / completed) using Ink or Blessed
• Displays findings grouped by severity (critical → info) after all agents complete
• Supports --range HEAD~3..HEAD to limit analysis to recent commits
• Exits with code 1 if any critical or high findings are present (CI-friendly)
• Respects review.ignorePatterns from config

Backlink: #1