Rewrite subagent-driven-development with executable flowcharts

- Add graphviz/dot flowcharts as primary executable instructions
- Extract prompt templates to separate collateral files:
  - ./implementer-prompt.md
  - ./spec-reviewer-prompt.md
  - ./code-quality-reviewer-prompt.md
- Use qualified skill names (superpowers:skill-name)
- Make flowchart labels explicit and action-oriented
- Add "When to Use" decision flowchart
- Keep detailed prose as supporting content

skills/subagent-driven-development/code-quality-reviewer-prompt.md

@@ -0,0 +1,20 @@
+# Code Quality Reviewer Prompt Template
+
+Use this template when dispatching a code quality reviewer subagent.
+
+**Purpose:** Verify implementation is well-built (clean, tested, maintainable)
+
+**Only dispatch after spec compliance review passes.**
+
+```
+Task tool (superpowers:code-reviewer):
+  Use template at requesting-code-review/code-reviewer.md
+
+  WHAT_WAS_IMPLEMENTED: [from implementer's report]
+  PLAN_OR_REQUIREMENTS: Task N from [plan-file]
+  BASE_SHA: [commit before task]
+  HEAD_SHA: [current commit]
+  DESCRIPTION: [task summary]
+```
+
+**Code reviewer returns:** Strengths, Issues (Critical/Important/Minor), Assessment