[Feature]: Rich execution completion report with metrics

[JeremyDev87]

Problem Statement

After successful execution, the completion comment only says "Implementation complete. Please check PR #N."
Users have no visibility into what was actually done — how many files changed, which steps were implemented,
or how large the diff is — without manually opening the PR.

Proposed Solution

Enhance the post-completion comment to include a rich execution report with:

• Summary table: PR number, branch name, commit count, changed files count (+additions, -deletions)
• Implemented steps: List of step commits parsed from git history
• Changed files: Compact list of modified file paths
• Link to workflow run log

Example Output

Item	Value
PR	#42
Branch	claude/issue-15
Commits	5
Changed files	8 (+340, -52)

Technical Approach

This is a pure post-processing enhancement — no changes to Claude prompts needed.

Files to modify:

• src/github.ts — Add getReportData() method using octokit.rest.repos.compareCommits()
• src/comment_builder.ts — Extend buildCompletionComment() to accept and render report data
• src/post_process_cli.ts — Extend runPostCompletion() to collect report data (add BASE_BRANCH env var)
• src/i18n.ts — Add translation keys: report_header, report_summary_pr, report_summary_commits, report_summary_files, report_steps_header, report_files_header, report_truncated

Edge cases:

• GitHub API returns max 300 files in compareCommits — add truncation disclaimer when files.length >= 300
• No PR found for branch — fall back to current simple completion comment

Acceptance Criteria

• Completion comment includes summary table with PR, branch, commits, and file stats
• Step commits are listed with their messages
• Changed file paths are shown in compact format
• Fallback to simple comment when report data unavailable
• All 8 languages have new translation keys
• Tests cover getReportData(), extended buildCompletionComment(), and runPostCompletion()

[github-actions]

⚠️ Leonidas Failed

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