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

Tools/README-Tools.md

@@ -125,6 +125,7 @@ The relationship is one-way: Tools act on state that other scripts have written.
 | `recreate_shares.sh` | Share directories missing after fresh install or disk rebuild | After fresh unRAID install or disk replacement on HOST2 |
 | `continuous_scripts_status.sh` | Need a live view of watchdog and fallback state | Any time — manual dashboard, no schedule |
 | `claude_startup.sh` | Claude Code session setup after reboot — symlinks persistent storage | After each unRAID reboot, or called by array_started.sh |
+| `docker_prune_images.sh` | Remove dangling or unused Docker images accumulated after updates | After update cycles, or when disk space is low |
 | `ramdisk_stop.sh` | Safely stop the transcode ramdisk — redirect symlink to SSD, unmount, update state | Before re-running ramdisk_setup.sh with new size or thresholds |
 | `emby_to_lidarr_sync.sh` | Add all Emby album artists not yet tracked in Lidarr | After Lidarr setup, database wipe, or when you suspect gaps |
 | `emby_to_sonarr_sync.sh` | Add all Emby TV series not yet tracked in Sonarr | After Sonarr setup, database wipe, or when you suspect gaps |