Docs audit fixes: kiosk code drift, PowerShell chains, broken links, leaks

From the Fable/Opus documentation audit (8 confirmed + verified
lab-drift the run's session limit had cut short):
- HIGH: the lab's kiosk _kiosk_find_item block showed the pre-stage-17
  row-id resolver as current; replace with the shipped gagelabtag /
  numeric-tail resolver, fix the stale 'resolved by row id' prose and
  the 'stage-7 code is corrected' note.
- MED: the badge _external_lookup block used dict-only row access that
  breaks on a tuple cursor; use the tuple-or-dict form shipped. Split
  '&&' command chains (fail in PowerShell 5.1) in the lab.
- LOW/link: the Windows note's [DEVELOPMENT-SETUP] link dropped the .md
  and 404'd in four docs; fix. Correct the stage-6a->16a comment and
  the lab-stage tag range (..16 -> ..17).
- Leaks: drop /home/camp path from ADR-006, the internal gitea host
  from PLUGINS.md.
- Windows: add an mklink junction note for the external-plugin symlink
  dev loop.
- CI: prime root to mysql_native_password so pymysql connects to the
  MySQL 8 service without the cryptography package (and its kit wheel).

docs/PLUGIN-GUIDE.md

@@ -8,7 +8,7 @@ way it does by walking the shipped code of the exemplar plugin.
 > **Windows / VS Code:** command examples use the Linux venv path
 > `venv/bin/python`; on Windows use `venv\Scripts\python` and
 > `$env:FLASK_APP="shopdb"` (not `export`). Full Windows onboarding:
-> [DEVELOPMENT-SETUP](DEVELOPMENT-SETUP).
+> [DEVELOPMENT-SETUP](DEVELOPMENT-SETUP.md).
 
 `measuringtools` was chosen as the exemplar on purpose. It is the first plugin
 built after the framework matured (ADR-005 scoped it; ADR-008 changed how plugin