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/adr/ADR-006-collector-contract.md

@@ -145,4 +145,4 @@ Migration path:
 - `shopdb/plugins/base.py` (`get_collector_schema` + `apply_collector_payload` hooks)
 - ADR-001 (asset model the collectors target)
 - ADR-002 (collector schema is part of plugin contract; changes to the hook signature are major bumps)
-- The PXE project (`/home/camp/projects/pxe/`) which feeds the computers collector
+- The PXE project (the PXE imaging project) which feeds the computers collector