Sync READMEs and manuals to current script headers

Fix discrepancies found by auditing docs against headers:
- stability_watchdog.sh: wrong variable name (STRIKES → STRIKE_LIMIT) and wrong default (2hr → 12hr) in header
- Watchdogs manual: REBOOT_WINDOW_HRS example value was 2, should be 12
- Transcodes README: transcode_cleanup/manager table said "Every 3 min", should be "Every 7 minutes"
- Tools manual: fallback_state_reset.sh still marked "not yet built" — rewrite section to reflect current script
- Tools manual: claude_startup --setup flag doesn't exist; modes were inverted — fix and add --launch
- Tools README + manual: add docker_prune_images.sh (existed but undocumented)
- Tools manual: add play_state_sync.sh --full to flag reference
- Orchestrators README: arrs_failed_stalled_recovery runs via intermediate_sync (every 4hr), not standalone every 6hr
- Plugin README: add build.sh to scripts table
- Partnership README + manual: add partnership_transfer.sh and onboard_cancel.sh to script tables and flag reference

Plugin/README-Plugin.md

@@ -76,6 +76,7 @@ so behaviour stays consistent without a shell dependency.
 | Script | Role | When It Runs |
 |--------|------|--------------|
 | `dev_install.sh` | Symlinks `Plugin/unraid/` into Unraid's web server | Once, manually, after cloning or moving the repo |
+| `build.sh` | Packages the plugin as a `.txz` for release | Before publishing a new plugin version |
 
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