chore: migrate legacy pre-commit hook to .pre-commit-config.yaml

Replaces shell script (.git/hooks/pre-commit.legacy) with ecosystem-managed pre-commit framework:
- gitleaks/gitleaks: secret scanning
- jumanjihouse/pre-commit-hooks: shellcheck wrapper
- pre-commit/pre-commit-hooks: JSON/YAML validation, end-of-file-fixer, trailing-whitespace
- local hooks: SKILL.md frontmatter validation

Uses pinned versions for reproducibility across environments. Includes auto-fixes from hook runs (formatting, trailing whitespace, JSON beautification).

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

plugins/kyberforge/docs/research/examples/skill-write/writing-great-skills/GLOSSARY.md

@@ -178,4 +178,4 @@ An instruction that changes nothing because the model already does it by default
 
 A leading word is a *technique*; No-Op is a *verdict* on a line — and they cross. A leading word too weak to beat the default is a no-op (_be thorough_ when the agent is already thorough-ish), and the fix is a stronger word that passes the verdict (_relentless_), not a different technique. So the No-Op test — does it change behaviour versus the default? — is also how you grade whether a leading word is earning its repetitions. This is model-relative, not reader-relative: two people disagreeing over whether a line is a no-op disagree about the default, and settle it by running the skill, not by debate.
 
-_Avoid_: redundant instruction, restating the obvious, belaboring
+_Avoid_: redundant instruction, restating the obvious, belaboring

plugins/kyberforge/docs/research/examples/skill-write/writing-great-skills/SKILL.md

@@ -79,4 +79,4 @@ Use these to diagnose issues the user may be having with the skill.
 - **Duplication** — the same meaning in more than one place. Costs maintenance and tokens, and inflates a meaning's prominence on the ladder past its real rank.
 - **Sediment** — stale layers that settle because adding feels safe and removing feels risky. The default fate of any skill without a pruning discipline.
 - **Sprawl** — a skill simply too long, even when every line is live and unique. Hurts readability and maintainability and wastes tokens. The cure is the ladder: disclose **reference** behind pointers, and split by **branch** or sequence so each path carries only what it needs.
-- **No-op** — a line the model already obeys by default, so you pay load to say nothing. The test: does it change behaviour versus the default? A weak leading word (_be thorough_ when the agent is already thorough-ish) is a no-op; the fix is a stronger word (_relentless_), not a different technique.
+- **No-op** — a line the model already obeys by default, so you pay load to say nothing. The test: does it change behaviour versus the default? A weak leading word (_be thorough_ when the agent is already thorough-ish) is a no-op; the fix is a stronger word (_relentless_), not a different technique.