refactor(skills): fold systematic-debugging Related-skills block into Phase 4

Same treatment as subagent-driven-development and executing-plans: the
test-driven-development entry duplicated the reference already at Phase 4
Step 1, and the verification-before-completion entry was a sole carrier —
it moves to its point of use in Phase 4 Step 3 (Verify Fix). Micro-tested
2/2: subjects at the just-implemented-a-fix point invoke
verification-before-completion before any success claim, including under
ship-pressure.

skills/executing-plans/SKILL.md

@@ -16,10 +16,11 @@ Load plan, review critically, execute all tasks, report when complete.
 ## The Process
 
 ### Step 1: Load and Review Plan
-1. Read plan file
-2. Review critically - identify any questions or concerns about the plan
-3. If concerns: Raise them with your human partner before starting
-4. If no concerns: Create todos for the plan items and proceed
+1. Ensure an isolated workspace: use superpowers:using-git-worktrees to create one or verify the existing one
+2. Read plan file
+3. Review critically - identify any questions or concerns about the plan
+4. If concerns: Raise them with your human partner before starting
+5. If no concerns: Create todos for the plan items and proceed
 
 ### Step 2: Execute Tasks
 
@@ -61,10 +62,3 @@ After all tasks complete and verified:
 - Reference skills when plan says to
 - Stop when blocked, don't guess
 - Never start implementation on main/master branch without explicit user consent
-
-## Integration
-
-**Required workflow skills:**
-- **superpowers:using-git-worktrees** - Ensures isolated workspace (creates one or verifies existing)
-- **superpowers:writing-plans** - Creates the plan this skill executes
-- **superpowers:finishing-a-development-branch** - Complete development after all tasks

skills/subagent-driven-development/SKILL.md

@@ -84,6 +84,9 @@ digraph process {
 
 ## Pre-Flight Plan Review
 
+Ensure the work happens in an isolated workspace: use
+superpowers:using-git-worktrees to create one or verify the existing one.
+
 Before dispatching Task 1, scan the plan once for conflicts:
 
 - tasks that contradict each other or the plan's Global Constraints
@@ -402,17 +405,3 @@ Done!
 **If subagent fails task:**
 - Dispatch fix subagent with specific instructions
 - Don't try to fix manually (context pollution)
-
-## Integration
-
-**Required workflow skills:**
-- **superpowers:using-git-worktrees** - Ensures isolated workspace (creates one or verifies existing)
-- **superpowers:writing-plans** - Creates the plan this skill executes
-- **superpowers:requesting-code-review** - Code review template for the final whole-branch review
-- **superpowers:finishing-a-development-branch** - Complete development after all tasks
-
-**Subagents should use:**
-- **superpowers:test-driven-development** - Subagents follow TDD for each task
-
-**Alternative workflow:**
-- **superpowers:executing-plans** - Use for parallel session instead of same-session execution

skills/systematic-debugging/SKILL.md

@@ -188,6 +188,7 @@ You MUST complete each phase before proceeding to the next.
    - Test passes now?
    - No other tests broken?
    - Issue actually resolved?
+   - Use the `superpowers:verification-before-completion` skill before claiming success
 
 4. **If Fix Doesn't Work**
    - STOP
@@ -283,10 +284,6 @@ These techniques are part of systematic debugging and available in this director
 - **`defense-in-depth.md`** - Add validation at multiple layers after finding root cause
 - **`condition-based-waiting.md`** - Replace arbitrary timeouts with condition polling
 
-**Related skills:**
-- **superpowers:test-driven-development** - For creating failing test case (Phase 4, Step 1)
-- **superpowers:verification-before-completion** - Verify fix worked before claiming success
-
 ## Real-World Impact
 
 From debugging sessions: