iso 1.26.1: ship /etc/felhom/ — the directory the bootstrap writes its state into

FIX for the Part-5 failure. felhom-bootstrap.sh writes the appliance token (:431), the pairing code
(:435) and .bootstrap-done into /etc/felhom/. The old stub-first-boot.sh created it explicitly
('install -d -m 0755 /etc/felhom /usr/local/sbin'); packaging dropped the env FILE correctly and the
DIRECTORY with it. Measured consequence on a real interactive install: the box registered at the hub,
could not persist its token, and polled 'HTTP 401 — still retrying' forever with no claim code.

- build-deb.sh now ships ./etc/felhom/ (0755, empty) and ASSERTS it, plus ./usr/local/sbin/ and
  ./lib/systemd/system/, as G13. RED-PROOFED: removing the install -d makes the build exit 3 with
  'is not in the package (G13)', and restoring it goes green.
- The gate gains G13 with the reasoning: G7/G8/G9 all passed on the broken package. G9 proves the
  payload is the right payload and says NOTHING about what the payload depends on.

ISO_VERSION -> 1.26.1.

scripts/iso/build-felhom-iso.sh

@@ -48,7 +48,7 @@ set -euo pipefail
 # does not exist: the ISO is a frozen artifact, while felhom-host-install.sh is fetched at RUN TIME
 # from the website's git-sync of `main` (R-94/R-110), so whatever version an ISO carries, the script a
 # box runs is always current. Coupling them would invent a constraint. The claim is corrected instead.
-ISO_VERSION="1.26.0"   # the ISO's own version. INDEPENDENT of felhom-host-install.sh's SCRIPT_VERSION,
+ISO_VERSION="1.26.1"   # the ISO's own version. INDEPENDENT of felhom-host-install.sh's SCRIPT_VERSION,
                        # which is fetched at run time from main and is not frozen into the image.
 IMAGE="${FELHOM_ISO_ASSISTANT_IMAGE:-felhom-iso-assistant:trixie}"
 HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"