SKILL.md frontmatter uses flow sequences which fail `agentskills validate`

[ytausch]

Problem

The SKILL.md frontmatter in this repo uses YAML flow sequences (JSON-style inline arrays):

---
name: gws-calendar
version: 1.0.0
description: "Google Calendar: Manage calendars and events."
metadata:
  openclaw:
    category: "productivity"
    requires:
      bins: ["gws"]
    cliHelp: "gws calendar --help"
---

The Agent Skills reference implementation (skills-ref) uses strictyaml to parse frontmatter, which intentionally rejects flow sequences. This means agentskills validate fails on all gws-cli skills:

$ uvx --from skills-ref agentskills validate skills/gws-calendar/
Validation failed for skills/gws-calendar:
  - Invalid YAML in frontmatter: While scanning
  in "<unicode string>", line 9, column 13:
          bins: ["gws"]
                ^ (line: 9)
Found ugly disallowed JSONesque flow mapping (surround with ' and ' to make text appear literally)
  in "<unicode string>", line 9, column 14:
          bins: ["gws"]
                 ^ (line: 9)

This affects all 92 skills since they all contain bins: ["gws"].

Reproducer

import strictyaml

strictyaml.load('bins: ["gws"]')
# strictyaml.exceptions.YAMLValidationError

vs. the block-style equivalent which works fine:

strictyaml.load('bins:\n  - gws')
# OK

Suggested fix

Replace flow sequences with block-style sequences in the frontmatter:

     requires:
-      bins: ["gws"]
+      bins:
+        - gws

This is valid YAML either way, but the block style is compatible with strictyaml.