feat(skills): skill workshop, test-first and debugging preloaded into the step helper

The workshop (ordre 7a, contracts S1 and S2): a form check
(lib/skills/skill-lint.mjs) that follows Claude Code's own skill fields,
and a model-free routing test (lib/skills/routing.mjs) over every skill,
the 7 commands and the 21 spawnable agents, reading the eval cases
themselves (evals/skill-*, 3 fire / 2 quiet / 1 effect, tagged with the
event they came from). Thresholds pinned, never lowered.

The two skills were written against failures measured first in helpers
without them: red only as an import crash, the whole suite run from a
hand-made file list instead of the repo's own command, and an
unreproduced fix shipped under authority pressure. step-implementer
preloads both through its skills: line; no tool list change.

Credits: addyosmani/agent-skills @9d0c60d, obra/superpowers @8ca22db,
mattpocock/skills @c55ee46 (MIT), Anthropic skill-creator (Apache-2.0).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

evals/skill-debugging-fires-1/graders/skill-fired.md

@@ -0,0 +1,5 @@
+---
+type: tool_used
+tool: Skill
+input_match: '"skill"\s*:\s*"(?:voyage:)?debugging"'
+---

evals/skill-debugging-fires-1/prompt.md

@@ -0,0 +1,10 @@
+---
+description: "Routing case: the debugging skill should fire on this request (the reserve path outside the pipeline)."
+expected_outcome: "Claude calls the Skill tool for voyage:debugging at least once."
+tags: [skill-trigger, skill=debugging, from=baseline-dbg-receipt]
+runs: 3
+max_turns: 4
+allowed_tools: [Read, Glob, Grep, Skill]
+---
+
+The receipt total is off by one cent and nobody knows why. Find the root cause before changing any code.