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-office-hours/SKILL.md

@@ -1,8 +1,6 @@
 ---
 name: gstack-openclaw-office-hours
-description: Product interrogation with six forcing questions. Two modes: startup diagnostic (demand reality, status quo, desperate specificity, narrowest wedge, observation, future-fit) and builder brainstorm. Use when asked to brainstorm, "is this worth building", "I have an idea", "office hours", or "help me think through this". Proactively use when user describes a new product idea or wants to think through design decisions before any code is written.
-version: 1.0.0
-metadata: { "openclaw": { "emoji": "🎯" } }
+description: Use when asked to brainstorm, evaluate whether an idea is worth building, run office hours, or think through a new product idea or design direction before any code is written.
 ---
 
 # YC Office Hours
@@ -281,8 +279,7 @@ Count the signals for the closing message.
 
 ## Phase 5: Design Doc
 
-Write the design document and save it to memory. After writing, tell the user:
-**"Design doc saved. Other skills (/plan-ceo-review, /plan-eng-review) will find it automatically."**
+Write the design document and save it to memory.
 
 ### Startup mode design doc template: