feat: /retro global — cross-project AI coding retrospective (v0.10.2.0) (#316)

* feat: gstack-global-discover — cross-tool AI session discovery

Standalone script that scans Claude Code, Codex CLI, and Gemini CLI
session directories, resolves each session's working directory to a git
repo, deduplicates by normalized remote URL, and outputs structured JSON.

- Reads only first 4-8KB of session files (avoids OOM on large transcripts)
- Only counts JSONL files modified within the time window (accurate counts)
- Week windows midnight-aligned like day windows for consistency
- 16 tests covering URL normalization, CLI behavior, and output structure

* feat: /retro global — cross-project retro using discovery engine

Adds Global Retrospective Mode to the /retro skill. When invoked as
`/retro global`, skips the repo-scoped retro and instead uses
gstack-global-discover to find all AI coding sessions across all tools,
then runs git log on each discovered repo for a unified cross-project
retrospective with global shipping streak and context-switching metrics.

* chore: bump version and changelog (v0.9.9.0)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: sync documentation with shipped changes

Update README /retro description to mention global mode.
Add bin/ directory to CLAUDE.md project structure.

* feat: /retro global adds per-project personal contributions breakdown

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: regenerate SKILL.md files after main merge

* chore: bump version and changelog (v0.10.2.0)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: test coverage catalog — shared audit across plan/ship/review (v0.10.1.0) (#259)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: /retro global shareable personal card — screenshot-ready stats

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: regenerate Codex/agents SKILL.md for retro shareable card

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: widen retro global card — never truncate repo names

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: retro global card — left border only, drop unreliable right border

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -78,7 +78,8 @@ gstack/
 ├── land-and-deploy/ # /land-and-deploy skill (merge → deploy → canary verify)
 ├── office-hours/    # /office-hours skill (YC Office Hours — startup diagnostic + builder brainstorm)
 ├── investigate/     # /investigate skill (systematic root-cause debugging)
-├── retro/           # Retrospective skill
+├── retro/           # Retrospective skill (includes /retro global cross-project mode)
+├── bin/             # Standalone scripts (gstack-global-discover for cross-tool session discovery)
 ├── document-release/ # /document-release skill (post-ship doc updates)
 ├── cso/             # /cso skill (OWASP Top 10 + STRIDE security audit)
 ├── design-consultation/ # /design-consultation skill (design system from scratch)