fix(webui): repair broken scenario Run button onclick, dedupe build.sh overlay staging

- page_scenario.go: onclick built via JSON.stringify() embedded raw double
  quotes inside a double-quoted HTML attribute, truncating the attribute so
  the click handler never compiled; pass the name through an escaped
  data-scenario-name attribute instead.
- build.sh: overlay staging rsyncs (OVERLAY_DIR->stage, stage->includes.chroot)
  ran without --delete, so a scenario removed from the repo (a9924b0) stayed
  baked into every ISO built from the persistent stage cache since — the
  "second script" in the Scenario page's list.
- blackbox: rewritten around a deterministic local zip + incremental
  patch-the-changed-suffix onto removable media, instead of walking/copying
  ~90 files through a synchronous ntfs-3g FUSE mount every cycle. journalctl
  captures are now "--since last sync" (were "--since boot", growing with
  uptime) and metrics.db is excluded (was copied whole every cycle).
- scenario: nvbandwidth-acs-ab now escalates GPU count (same-socket pair,
  other socket's pair, one cross-socket pair, all GPUs) under each ACS state
  instead of always running all 6 GPUs at once, using a new `bee
  gpu-bandwidth-groups` subcommand that discovers socket layout from
  `nvidia-smi topo -m` at runtime — gpu_indices is host-specific, so this
  can't be baked into the scenario file.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

iso/builder/build.sh

@@ -1460,7 +1460,7 @@ elif [ -d "${LB_PKG_CACHE}" ] && [ "$(ls -A "${LB_PKG_CACHE}" 2>/dev/null)" ]; t
     rsync -a "${LB_PKG_CACHE}/" "${BUILD_WORK_DIR}/cache/packages.chroot/"
 fi
 
-rsync -a "${OVERLAY_DIR}/" "${OVERLAY_STAGE_DIR}/"
+rsync -a --delete "${OVERLAY_DIR}/" "${OVERLAY_STAGE_DIR}/"
 rm -f \
     "${OVERLAY_STAGE_DIR}/etc/bee-ssh-password-fallback" \
     "${OVERLAY_STAGE_DIR}/etc/bee-release" \
@@ -1734,7 +1734,7 @@ fi
 LB_DIR="${BUILD_WORK_DIR}"
 LB_INCLUDES="${LB_DIR}/config/includes.chroot"
 mkdir -p "${LB_INCLUDES}"
-rsync -a "${OVERLAY_STAGE_DIR}/" "${LB_INCLUDES}/"
+rsync -a --delete "${OVERLAY_STAGE_DIR}/" "${LB_INCLUDES}/"
 
 # Ensure SSH authorized_keys perms are correct (rsync may alter)
 if [ -f "${LB_INCLUDES}/root/.ssh/authorized_keys" ]; then