feat(kyberforge): add pc-author and pc-run pre-commit skills

## Why
Pre-commit config management was entirely manual — no skill existed to
help create, modify, or validate `.pre-commit-config.yaml`, or to run,
install, and maintain the pre-commit setup. These two skills close that
gap with clear scope separation: authoring vs. execution.

## Implementation Notes
- `pc-author` owns `.pre-commit-config.yaml` only (no hook publishing,
  no install). Runs `pre-commit validate-config` after every write.
  Shallow file-extension scan drives proactive hook recommendations;
  rev staleness is flagged against `references/hooks-by-language.md`
  rather than hardcoded versions. Remove path reverts on failure.
- `pc-run` owns install, run, autoupdate, gc, and clean. Defaults to
  `--all-files`. Install warns about existing `.git/hooks/` files being
  overwritten by `-f`. Clean requires HITL confirmation. Failure
  interpretation delegates to `references/failure-patterns.md`.
- Provenance wired to `plugins/kyberforge/docs/research/docs/pre-commit/`.
- Both skills resolve via the existing `"skills/"` glob in `plugin.json`.

## Impact
Two new slash commands available after `claude plugin install kyberforge@holocron`:
`/pc-author` and `/pc-run`.

Refs: #12

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01P87CiC58Ru2PPWYTeXtjHT

plugins/kyberforge/skills/pc-run/references/sources.md

@@ -0,0 +1,33 @@
+# Sources
+
+## context7-pre-commit-com
+
+- **URL:** context7:/pre-commit/pre-commit.com
+- **Description:** Official pre-commit.com documentation — installation, configuration schema, CLI reference, hook authoring, advanced features, troubleshooting
+- **Contributing files:** SKILL.md, references/failure-patterns.md
+- **Research doc:** plugins/kyberforge/docs/research/docs/pre-commit/sources.md
+- **Status:** `extracted`
+
+## pre-commit-com
+
+- **URL:** https://pre-commit.com/
+- **Description:** Pre-commit framework homepage — full docs covering install, config, CLI, hook authoring, stages, local hooks, meta hooks, hazmat helpers, CI integration
+- **Contributing files:** SKILL.md, references/failure-patterns.md
+- **Research doc:** plugins/kyberforge/docs/research/docs/pre-commit/sources.md
+- **Status:** `extracted`
+
+## context7-pre-commit-hooks
+
+- **URL:** context7:/pre-commit/pre-commit-hooks
+- **Description:** Official pre-commit-hooks collection — all available hook IDs with options and examples
+- **Contributing files:** (none)
+- **Research doc:** plugins/kyberforge/docs/research/docs/pre-commit/sources.md
+- **Status:** `extracted`
+
+## pre-commit-hooks-github
+
+- **URL:** https://raw.githubusercontent.com/pre-commit/pre-commit-hooks/main/README.md
+- **Description:** Official pre-commit-hooks README — complete hook listing with all args, categories, deprecated hooks, and latest version
+- **Contributing files:** (none)
+- **Research doc:** plugins/kyberforge/docs/research/docs/pre-commit/sources.md
+- **Status:** `extracted`