docs: fix markdown lint, broken links, stale counts, and publishing guidance

- Fix broken ToC anchors in competitive-analysis.md (MD051)
- Add blank lines before code blocks in api-reference.md (MD031)
- Add language identifiers to directory tree code blocks in MARKETPLACE.md and skills/unraid/README.md (MD040)
- Fix size unit guidance conflict: clarify disk sizes are KB, memory is bytes
- Update stale "90 actions" references to "76 actions" across research docs
- Fix coverage table terminology and clarify 22% coverage calculation
- Recommend PyPI Trusted Publishing (OIDC) over API token secrets in PUBLISHING.md
- Update action count in .claude-plugin/README.md

Resolves review threads: PRRT_kwDOO6Hdxs5uvO2m, PRRT_kwDOO6Hdxs5uvO2o,
PRRT_kwDOO6Hdxs5uvO2r, PRRT_kwDOO6Hdxs5uvOcl, PRRT_kwDOO6Hdxs5uvOcr,
PRRT_kwDOO6Hdxs5uvKrq, PRRT_kwDOO6Hdxs5uvO2u, PRRT_kwDOO6Hdxs5uvO2w,
PRRT_kwDOO6Hdxs5uvO2z, PRRT_kwDOO6Hdxs5uu7zl

skills/unraid/README.md

@@ -8,7 +8,7 @@ This skill provides complete access to all 27 read-only Unraid GraphQL API endpo
 
 ### Files
 
-```
+```text
 skills/unraid/
 ├── SKILL.md                           # Main skill documentation
 ├── README.md                          # This file
@@ -147,7 +147,7 @@ This skill activates when you mention:
 
 ## Notes
 
-- All sizes are in **kilobytes**
+- Disk/array sizes are in **kilobytes**; memory values (from `info.memory` and `metrics.memory`) are in **bytes**
 - Temperatures are in **Celsius**
 - Docker container logs are **not accessible** via API (use SSH)
 - Poll no faster than every **5 seconds** to avoid server load