docs: post-merge sync for v6.7.0 — version footers + changelog (#371)

Co-authored-by: Test User <test@example.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: 3 people

docs/CHANGELOG.md

@@ -6,6 +6,23 @@ The format follows [Keep a Changelog](https://keepachangelog.com/), and this pro
 
 ---
 
+## [6.7.0] - 2026-02-10
+
+### Added
+
+- **Display math validation** — pure ZSH state machine (`_check_math_blanks`) detects blank lines and unclosed `$$` blocks in `.qmd` files (PR #368)
+- **Pre-commit gate** — lint-staged validates `.qmd` files at commit time via `scripts/check-math.zsh`
+- **Deploy preflight: math check** — display math validation runs as check 3 of 5 during `teach deploy`; CI mode blocks, interactive warns
+- **Quality Gates documentation** — new `docs/guides/QUALITY-GATES.md` mapping every validation layer from keystroke to production
+- **41 new test assertions** across 3 suites (unit, E2E with sandboxed repos, dogfood against demo course)
+
+### Changed
+
+- Deploy preflight checks renumbered: unpushed commits → check 4, production conflicts → check 5
+- Test suite: 42/42 passing (143 test files, up from 140)
+
+---
+
 ## [6.6.0] - 2026-02-09
 
 ### Added

docs/guides/QUALITY-GATES.md

@@ -247,4 +247,4 @@ Areas where validation could be added in the future:
 ---
 
 **Last Updated:** 2026-02-10
-**Version:** v6.6.0
+**Version:** v6.7.0

docs/guides/TEACH-DEPLOY-GUIDE.md

@@ -1224,5 +1224,5 @@ The deployment summary box now includes a direct link to your GitHub Actions pag
 
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-**Last Updated:** 2026-02-09
-**Version:** v6.6.0
+**Last Updated:** 2026-02-10
+**Version:** v6.7.0

docs/reference/REFCARD-DEPLOY-V2.md

@@ -303,4 +303,4 @@ teach deploy --ci -d -m "Auto-deploy from GitHub Actions"
 
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-*v6.6.0 - teach deploy v2 with safety enhancements*
+*v6.7.0 - teach deploy v2 with math preflight + quality gates*

docs/reference/REFCARD-TEACH-DISPATCHER.md

@@ -449,6 +449,6 @@ teach status --performance        # Review metrics
 
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-**Version:** v6.6.0
-**Last Updated:** 2026-02-08
+**Version:** v6.7.0
+**Last Updated:** 2026-02-10
 **Commands:** 30 total (9 Scholar wrappers + 5 course mgmt + 6 content mgmt + 9 infrastructure + 1 discovery)