feat: add proactive triggers to all workflow skills

Every skill now has "Proactively suggest when..." language so Claude
surfaces skills at natural moments — not just when the user says
specific trigger phrases.

plan-design-review/SKILL.md

@@ -7,6 +7,8 @@ description: |
   then fixes the plan to get there. Works in plan mode. For live site
   visual audits, use /design-review. Use when asked to "review the design plan"
   or "design critique".
+  Proactively suggest when the user has a plan with UI/UX components that
+  should be reviewed before implementation.
 allowed-tools:
   - Read
   - Edit
@@ -32,8 +34,13 @@ _BRANCH=$(git branch --show-current 2>/dev/null || echo "unknown")
 echo "BRANCH: $_BRANCH"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
+_PROACTIVE=$(~/.claude/skills/gstack/bin/gstack-config get proactive 2>/dev/null || echo "true")
+echo "PROACTIVE: $_PROACTIVE"
 ```
 
+If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills — only invoke
+them when the user explicitly asks. The user opted out of proactive suggestions.
+
 If output shows `UPGRADE_AVAILABLE <old> <new>`: read `~/.claude/skills/gstack/gstack-upgrade/SKILL.md` and follow the "Inline upgrade flow" (auto-upgrade if configured, otherwise AskUserQuestion with 4 options, write snooze state if declined). If `JUST_UPGRADED <from> <to>`: tell user "Running gstack v{to} (just updated!)" and continue.
 
 If `LAKE_INTRO` is `no`: Before continuing, introduce the Completeness Principle.

plan-design-review/SKILL.md.tmpl

@@ -7,6 +7,8 @@ description: |
   then fixes the plan to get there. Works in plan mode. For live site
   visual audits, use /design-review. Use when asked to "review the design plan"
   or "design critique".
+  Proactively suggest when the user has a plan with UI/UX components that
+  should be reviewed before implementation.
 allowed-tools:
   - Read
   - Edit