feat: add trigger phrases to skill descriptions for better model matching

Anthropic's skill best practices: "the description field is not a summary —
it's when to trigger." Add explicit "Use when asked to..." phrases to 12 skill
descriptions so Claude's auto-discovery works with natural language requests
like "deploy this" or "check my diff", not just explicit /slash-commands.

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

gstack-upgrade/SKILL.md

@@ -3,7 +3,8 @@ name: gstack-upgrade
 version: 1.1.0
 description: |
   Upgrade gstack to the latest version. Detects global vs vendored install,
-  runs the upgrade, and shows what's new.
+  runs the upgrade, and shows what's new. Use when asked to "upgrade gstack",
+  "update gstack", or "get latest version".
 allowed-tools:
   - Bash
   - Read

gstack-upgrade/SKILL.md.tmpl

@@ -3,7 +3,8 @@ name: gstack-upgrade
 version: 1.1.0
 description: |
   Upgrade gstack to the latest version. Detects global vs vendored install,
-  runs the upgrade, and shows what's new.
+  runs the upgrade, and shows what's new. Use when asked to "upgrade gstack",
+  "update gstack", or "get latest version".
 allowed-tools:
   - Bash
   - Read