Strengthen using-superpowers for explicit skill requests

Addresses failure mode where Claude skips skill invocation even when
user explicitly requests it by name (e.g., "subagent-driven-development,
please").

Skill changes:
- "Check for skills" → "Invoke relevant or requested skills"
- "BEFORE ANY RESPONSE" → "BEFORE any response or action"
- Added reassurance that wrong skill invocations are okay
- New red flag: "I know what that means"

Tests:
- New test suite for explicit skill requests
- Single-turn and multi-turn scenarios with --continue
- Tests with haiku model and user CLAUDE.md

skills/using-superpowers/SKILL.md

@@ -21,7 +21,7 @@ This is not negotiable. This is not optional. You cannot rationalize your way ou
 
 ## The Rule
 
-**Check for skills BEFORE ANY RESPONSE.** This includes clarifying questions. Even 1% chance means invoke the Skill tool first.
+**Invoke relevant or requested skills BEFORE any response or action.** Even a 1% chance a skill might apply means that you should invoke the skill to check. If an invoked skill turns out to be wrong for the situation, you don't need to use it.
 
 ```dot
 digraph skill_flow {
@@ -62,6 +62,7 @@ These thoughts mean STOP—you're rationalizing:
 | "The skill is overkill" | Simple things become complex. Use it. |
 | "I'll just do this one thing first" | Check BEFORE doing anything. |
 | "This feels productive" | Undisciplined action wastes time. Skills prevent this. |
+| "I know what that means" | Knowing the concept ≠ using the skill. Invoke it. |
 
 ## Skill Priority