fix(openclaw): make native skills codex-friendly (#864)

Normalizes YAML frontmatter on the 4 hand-authored OpenClaw skills so stricter
parsers like Codex can load them. Codex CLI was rejecting these files with
"mapping values are not allowed in this context" on colons inside unquoted
description scalars.

- Drops non-standard `version` and `metadata` fields
- Rewrites descriptions into simple "Use when..." form (no inline colons)
- Adds a regression test enforcing strict frontmatter (name + description only)

Verified live: Codex CLI now loads the skills without errors. Observed during
/codex outside-voice run on the eval-community-prs plan review — Codex stderr
tripped on these exact files, which was real-world confirmation the fix is needed.

Dropped the connect-chrome changes from the original PR (the symlink removal is
out of scope for this fix; keeping connect-chrome -> open-gstack-browser).

Co-Authored-By: Cathryn Lavery <cathrynlavery@users.noreply.github.com>
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

openclaw/skills/gstack-openclaw-retro/SKILL.md

@@ -1,8 +1,6 @@
 ---
 name: gstack-openclaw-retro
-description: Weekly engineering retrospective. Analyzes commit history, work patterns, and code quality metrics with persistent history and trend tracking. Team-aware with per-person contributions, praise, and growth areas. Use when asked for weekly retro, what shipped this week, or engineering retrospective.
-version: 1.0.0
-metadata: { "openclaw": { "emoji": "📊" } }
+description: "Weekly engineering retrospective. Analyzes commit history, work patterns, and code quality metrics with persistent history and trend tracking. Team-aware with per-person contributions, praise, and growth areas. Use when asked for weekly retro, what shipped this week, or engineering retrospective."
 ---
 
 # Weekly Engineering Retrospective
@@ -25,11 +23,6 @@ Parse the argument to determine the time window. Default to 7 days. All times sh
 
 ---
 
-### Non-git context (optional)
-
-Check memory for non-git context: meeting notes, calendar events, decisions, and other
-context that doesn't appear in git history. If found, incorporate into the retro narrative.
-
 ### Step 1: Gather Raw Data
 
 First, fetch origin and identify the current user: