refactor(plugin)!: ship as a Claude Code plugin, one dir link per harness

Skills move to skills/<name>/SKILL.md and the repo gains both manifests, so
it is now a marketplace hosting exactly one plugin whose root is the repo
root (source: "."). Claude Code installs it from git; no symlinks involved.

Why: install.sh wired the library into every consuming repo as an ABSOLUTE
symlink to $CHECKOUT_DIR. The checkout moved three times, most recently when
local-dev@1966d5a dropped the embedded .skills/ copy, and nothing migrated
the links — 243 dangling links across 12 repos, hidden from git by the
**/.claude/skills/ ignore rule. Worse, ~/dev spans two path roots
(/Users/mathias on the iCloud-shared Macs, /home/mathias on koala), so an
absolute link stored there is broken on one side by construction. Re-running
the installer cannot fix that; only removing the mechanism can.

install.sh keeps the harnesses with no plugin system and drops from 42 links
per harness to one directory link, via the convergent ~/.agents/skills
convention that Pi and OpenCode both read:

  ~/.agents/skills          -> $CHECKOUT_DIR/skills
  ~/.config/crush/skills    -> ~/.agents/skills
  ~/.config/opencode/skills -> ~/.agents/skills

wire_claude_repo is deleted outright rather than gated behind a flag — on a
mixed-root fleet it cannot be made correct. Antigravity and Vibe targets go
too; both unused. CHECKOUT_DIR keeps its host-local default deliberately:
pointing it into ~/dev would put a git working tree inside iCloud with two
concurrent writers.

Taskfile drops five near-identical wiring loops (they had already drifted)
and delegates to install.sh. `task check` gains frontmatter validation, a
stray-root-entry gate, and manifest/tag version parity — the loose
secret-hygiene.md sat unloadable for months because nothing checked layout.

Verified: claude plugin validate . passes clean; a probe skill loaded as
skills:zzprobe through --plugin-dir; task check green at 42 skills.

Refs: #23
Bump-Type: minor

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BeAp5LTscnz2W7Ubt4eJ6m

skills/superpowers-requesting-code-review/SKILL.md

@@ -0,0 +1,103 @@
+---
+name: requesting-code-review
+description: Use when completing tasks, implementing major features, or before merging to verify work meets requirements
+---
+
+# Requesting Code Review
+
+Dispatch a code reviewer subagent to catch issues before they cascade. The reviewer gets precisely crafted context for evaluation — never your session's history. This keeps the reviewer focused on the work product, not your thought process, and preserves your own context for continued work.
+
+**Core principle:** Review early, review often.
+
+## When to Request Review
+
+**Mandatory:**
+- After each task in subagent-driven development
+- After completing major feature
+- Before merge to main
+
+**Optional but valuable:**
+- When stuck (fresh perspective)
+- Before refactoring (baseline check)
+- After fixing complex bug
+
+## How to Request
+
+**1. Get git SHAs:**
+```bash
+BASE_SHA=$(git rev-parse HEAD~1)  # or origin/main
+HEAD_SHA=$(git rev-parse HEAD)
+```
+
+**2. Dispatch code reviewer subagent:**
+
+Use Task tool with `general-purpose` type, fill template at `code-reviewer.md`
+
+**Placeholders:**
+- `{DESCRIPTION}` - Brief summary of what you built
+- `{PLAN_OR_REQUIREMENTS}` - What it should do
+- `{BASE_SHA}` - Starting commit
+- `{HEAD_SHA}` - Ending commit
+
+**3. Act on feedback:**
+- Fix Critical issues immediately
+- Fix Important issues before proceeding
+- Note Minor issues for later
+- Push back if reviewer is wrong (with reasoning)
+
+## Example
+
+```
+[Just completed Task 2: Add verification function]
+
+You: Let me request code review before proceeding.
+
+BASE_SHA=$(git log --oneline | grep "Task 1" | head -1 | awk '{print $1}')
+HEAD_SHA=$(git rev-parse HEAD)
+
+[Dispatch code reviewer subagent]
+  DESCRIPTION: Added verifyIndex() and repairIndex() with 4 issue types
+  PLAN_OR_REQUIREMENTS: Task 2 from docs/superpowers/plans/deployment-plan.md
+  BASE_SHA: a7981ec
+  HEAD_SHA: 3df7661
+
+[Subagent returns]:
+  Strengths: Clean architecture, real tests
+  Issues:
+    Important: Missing progress indicators
+    Minor: Magic number (100) for reporting interval
+  Assessment: Ready to proceed
+
+You: [Fix progress indicators]
+[Continue to Task 3]
+```
+
+## Integration with Workflows
+
+**Subagent-Driven Development:**
+- Review after EACH task
+- Catch issues before they compound
+- Fix before moving to next task
+
+**Executing Plans:**
+- Review after each task or at natural checkpoints
+- Get feedback, apply, continue
+
+**Ad-Hoc Development:**
+- Review before merge
+- Review when stuck
+
+## Red Flags
+
+**Never:**
+- Skip review because "it's simple"
+- Ignore Critical issues
+- Proceed with unfixed Important issues
+- Argue with valid technical feedback
+
+**If reviewer wrong:**
+- Push back with technical reasoning
+- Show code/tests that prove it works
+- Request clarification
+
+See template at: requesting-code-review/code-reviewer.md