skills: split oversized SKILL.md files into references/ (f3s pattern)

Break up the three most monolithic flat skills into a slim SKILL.md plus a
references/ directory of focused sub-files, matching the f3s and
agent-task-management structure. Pure reorganization: all content and meaning
preserved, only moved behind a reference index with resolving links.

- blog-writing-style (619->216): extract the Wikipedia-based 'Signs of AI
  writing' deep catalog into references/signs-of-ai-writing.md.
- check-shopping-status (319->135): extract references/imap-scan-script.md
  (steps 1-3 Python) and references/amazon-cdp.md (CDP login helper).
- photo-processing (232->155): extract references/auto-enhance.md (standalone
  ImageMagick auto-enhance script).

Adds notes/skills-review-2026-06-19.md with the full inventory and the
follow-up task IDs (dq0, eq0, fq0) for the remaining oversized skills.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 68 insertions, 0 deletions

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+# Skills review — 2026-06-19 (task 5q0)
+
+Reviewed all skills under `prompts/skills/` for DRY, clarity, and structure,
+and broke up the most oversized monolithic `SKILL.md` files into a slim
+`SKILL.md` + `references/` sub-files, matching the `f3s` /
+`agent-task-management` pattern.
+
+## Inventory (SKILL.md line counts, before this task)
+
+Top flat skills *without* a `references/` dir (split candidates):
+
+| Skill | Lines (before) | Action |
+|---|---|---|
+| blog-writing-style | 619 | **Split** → 216 |
+| check-shopping-status | 319 | **Split** → 135 |
+| photo-processing | 232 | **Split** → 155 |
+| llm-benchmark-comparison | 225 | Follow-up task dq0 |
+| music-collection | 217 | Follow-up task eq0 |
+| c-best-practices | 187 | Follow-up task fq0 |
+
+Everything else was ≤ 150 lines and reads coherently as a single file.
+
+Already well-structured (slim SKILL.md + `references/`), left untouched:
+`100-go-mistakes`, `agent-task-management`, `beyond-solid-principles`,
+`f3s`, `persona`, `pkgrepo`, `rocky-vm-setup`, `solid-principles`.
+
+Per the task brief, the just-restructured `agent-task-management`,
+`go-best-practices`, and `f3s` were left alone.
+
+## What changed (reorganization only — no content dropped)
+
+### blog-writing-style (619 → 216)
+- Extracted the large Wikipedia-based "Signs of AI writing" half into
+  `references/signs-of-ai-writing.md` (voice calibration, personality/soul,
+  the 29 numbered AI patterns with before/after examples, the full worked
+  example, process/output format).
+- SKILL.md keeps the foo.zone-specific de-LLM workflow plus a reference index
+  and inline pointers to the deep catalog.
+
+### check-shopping-status (319 → 135)
+- Extracted `references/imap-scan-script.md` (the read-only Python one-shot
+  script for steps 1–3) and `references/amazon-cdp.md` (the Chrome
+  DevTools-Protocol login sequence + reusable Python helper).
+- SKILL.md keeps the workflow prose, classification/carrier tables, status
+  badges, and tips, with a reference index and inline links.
+
+### photo-processing (232 → 155)
+- Extracted the standalone ImageMagick auto-enhance tool into
+  `references/auto-enhance.md` (`auto-enhance-photos.sh`, per-flag table,
+  output naming, saturation tuning).
+- SKILL.md keeps the dedup/burst/sharpness/staged-deletion culling workflow
+  with a reference index.
+
+All reference links verified to resolve to existing files.
+
+## Follow-up tasks created
+
+- `dq0` — split `llm-benchmark-comparison` (225 lines) into references/
+- `eq0` — split `music-collection` (217 lines) into references/
+- `fq0` — consider splitting `c-best-practices` (187 lines) into references/
+
+## DRY / clarity notes
+
+No cross-skill duplicated boilerplate worth deduplicating was found beyond the
+expected, intentional cross-references (e.g. blog skills referencing each
+other, check-shopping-status referencing protonbridge-imap). The SOLID /
+beyond-solid / auditing-code-quality skills already delegate cleanly rather
+than duplicating principle text.