merge: resolve conflicts with origin/main (v0.8.4)

Merge main into garrytan/fix-slug-clean, resolving conflicts in
templates, gen-skill-docs, and tests. All multi-line eval+mkdir+echo
blocks in merged templates use gstack-review-log/gstack-review-read
helpers. gstack-review-read now includes ---HEAD--- section for
main's commit staleness tracking feature.

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

CLAUDE.md

@@ -69,6 +69,8 @@ gstack/
 ├── review/          # PR review skill
 ├── plan-ceo-review/ # /plan-ceo-review skill
 ├── plan-eng-review/ # /plan-eng-review skill
+├── office-hours/    # /office-hours skill (YC Office Hours — startup diagnostic + builder brainstorm)
+├── debug/           # /debug skill (systematic root-cause debugging)
 ├── retro/           # Retrospective skill
 ├── document-release/ # /document-release skill (post-ship doc updates)
 ├── setup            # One-time setup: build binary + symlink skills
@@ -164,6 +166,8 @@ CHANGELOG.md is **for users**, not contributors. Write it like product release n
 
 - Lead with what the user can now **do** that they couldn't before. Sell the feature.
 - Use plain language, not implementation details. "You can now..." not "Refactored the..."
+- **Never mention TODOS.md, internal tracking, eval infrastructure, or contributor-facing
+  details.** These are invisible to users and meaningless to them.
 - Put contributor/internal changes in a separate "For contributors" section at the bottom.
 - Every entry should make someone think "oh nice, I want to try that."
 - No jargon: say "every question now tells you which project and branch you're in" not