chore(debug): fold in two techniques, delete systematic-debugging

superpowers-systematic-debugging restated debug's core (hypothesis before fix)
across 296 lines, with a fix-implementation phase that belongs to tdd and a
rationalization table that mostly repeats debug's own Anti-Patterns. Two things
in it were not restatement, and both are now in debug: instrument every
component boundary before hypothesising when a bug spans components, and treat
three failed fixes as evidence the mechanism was never identified rather than
as a reason to try a fourth.

Not deleted with it, contrary to the issue: find-polluter.sh and the three
technique files (root-cause-tracing, defense-in-depth, condition-based-waiting)
are real assets, one of them an actual tool. They move to debug/references/ with
a stated load trigger each, because a reference nobody knows when to open is
dead weight. The pressure-test transcripts and CREATION-LOG from the upstream
fork go; they document obra's process, not ours.

Pressure-tested per #19, and the RED phase refuted the issue's premise. Two
subagents without the skill got the multi-component scenario and the four-failed-
fixes scenario; both already instrumented boundaries unprompted, and the second
refused to write a fifth fix on its own initiative. So these sections are not
correcting a demonstrated gap in this model — they are insurance for weaker
models and for prompts less well-posed than a test scenario. Recorded as such
rather than claimed as a fix.

The GREEN run applied both sections correctly and then found four defects in
them, all fixed here: the boundary rule read as suspending Iron Law 2's 3-5
hypotheses; the trigger said "reduced" when fixes that change nothing are the
stronger signal; "stop proposing a fourth" read as licence to return no
hypotheses at all; and the references had no load triggers. Its remaining
findings are pre-existing and filed as #36.

41 skills. debug 146 -> 188 lines.

Closes #14
Bump-Type: minor

SKILLS_INDEX.md

@@ -39,7 +39,6 @@ the SKILL.md, not the table.
 | `superpowers-receiving-code-review` | Acting on received review feedback | Responding to review comments | claude-code, library |
 | `superpowers-requesting-code-review` | Requesting a code review well | Asking another agent/human to review | claude-code, library |
 | `superpowers-subagent-driven-development` | Subagent-driven development workflow | Building via orchestrated subagents | claude-code, library |
-| `superpowers-systematic-debugging` | Hypothesis-first systematic debugging | Diagnosing a failure methodically | claude-code, library |
 | `superpowers-using-git-worktrees` | Isolating work with git worktrees | Parallel/isolated work in a worktree | claude-code, library |
 | `superpowers-using-superpowers` | Meta: orienting in the superpowers set | Learning how to use the superpowers skills | claude-code, library |
 | `superpowers-verification-before-completion` | Verify behavior before claiming done | Before marking any task complete | claude-code, library |