Initial: BESser umbrella for BES2600 driver mainlining

Sets up the BES2600 mainlining work tree with:

- README: project overview, hardware target, driver lineage
  (CW1200 -> Bestechnic -> arjan-vlek -> Mobian/danctnix), patch series
  status, repo map, build/deploy workflow.

- patches/: c1 patch generated by git format-patch from
  marfrit/bes2600-dkms branch bes2600/factory-request-firmware
  (checkpatch.pl --no-tree --strict: 0 errors / 0 warnings / 0 checks).

- scripts/: build-bes2600-on-ohm.sh, deploy-c1-to-ohm.sh,
  backup-ohm-kernel.sh - reproducible build + deploy + backup.

- fw-analysis/: per-blob strings.txt + fnnames.txt extracted from the
  4 firmware blobs pulled from ohm 2026-04-21. Source binaries NOT
  committed (Bestechnic-proprietary).

- notes/: observed-bugs.md (4 known bug surfaces with file:line +
  patch-series cross-reference), source-map.md (every public driver
  source variant + their canonical role).

Companion work tree: marfrit/bes2600-dkms (Mobian DKMS fork) at
git.reauktion.de.

Signed-off-by: Markus Fritsche <fritsche.markus@gmail.com>

scripts/backup-ohm-kernel.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+# Snapshot kernel + modules + bes2600 firmware from ohm into ~/backup/.
+#
+# Per feedback_backup_before_replace.md: always backup before replacing
+# kernel/modules/configs, with versioned labels.
+
+set -e
+
+TS=$(date +%Y%m%d-%H%M%S)
+KVER=$(uname -r)
+DEST=/home/mfritsche/backup
+mkdir -p ${DEST}
+
+OUT=${DEST}/ohm-kernel-${KVER}-${TS}.tar.zst
+
+echo "=== Sizes ==="
+sudo du -sh /boot /lib/modules/${KVER} /lib/firmware/bes2600
+
+echo "=== Tar ==="
+sudo tar --use-compress-program='zstd -3' \
+    -cf "${OUT}" \
+    -C / boot lib/modules/${KVER} lib/firmware/bes2600
+sudo chown $(id -un):$(id -gn) "${OUT}"
+
+echo "=== Result ==="
+ls -lah "${OUT}"
+zstd -t "${OUT}" 2>&1 | tail -1