fleet/ohm: switch bes2600 driver scope to cumulative-c5x-danctnix interim (closes #5 partial migration)

Audit during ohm pkgrel=4 migration found the per-series -danctnix
mirrors merged in #17 do NOT apply against the linux-pinetab2 baseline:
all 17 of them use DKMS-style root paths (bes2600/foo.c) rather than
in-tree staging paths (drivers/staging/bes2600/foo.c), and at least one
has a corrupted mixed-prefix header
(a/drivers/staging/bes2600/...  b/bes2600/...).

ka-promote ohm with those includes produced a 172 644-byte cumulative
touching 27 file paths, of which 11 are bogus. The hand-curated
0001-bes2600-besser-cumulative-series.patch from the working
danctnix-besser-pkgbuild flow on boltzmann (148 149 bytes, 48 in-tree
staging files) is what pkgrel=3 actually builds with.

Until the per-series mirrors are reconstructed (followup issue to be
opened separately), the bes2600 driver scope is satisfied here by
staging that hand-curated cumulative as a single-file series-dir
patches/driver/bes2600/cumulative-c5x-danctnix/. ohm.yaml drops the
broken per-series includes in favour of:

  - driver/bes2600/cumulative-c5x-danctnix/
  - driver/bes2600/scan-filter-5ghz-danctnix/      (closes besser#1)
  - arch/arm64/xor-neon-ffixed-x18-scs-build-fix-danctnix/

ka-promote ohm now produces a self-consistent 157 446-byte cumulative
(148 149 + 7 735 + 1 562 = exact byte arithmetic) with b2sum
a807297b25be... which is what the new
marfrit-packages/arch/linux-pinetab2-danctnix-besser PKGBUILD pkgrel=4
pins.

Also fixes fleet/ohm.yaml YAML parse error: bar5_burn_in had a scalar
value followed by a sub-list, which ka-promote (PyYAML) refused to
parse. The whole manifest had never parsed cleanly since #18 landed.

Refs: #5 (migrate PKGBUILD), #2 (mirror besser series — needs per-series
rewrite followup), besser#1 (Patch I).

patches/driver/bes2600/cumulative-c5x-danctnix/README.md

@@ -0,0 +1,35 @@
+# cumulative-c5x-danctnix — interim single-file cumulative
+
+**Series role**: ohm manifest's bes2600 driver patchset, c5x stack as
+shipped in `linux-pinetab2-danctnix-besser` pkgrel=3 on 2026-05-18.
+
+## Why this is a single .patch and not split per-fix
+
+The 12-ish per-series mirror PR (kernel-agent#17) of the boltzmann-side
+`marfrit/besser` series produced patches with DKMS-style paths
+(`bes2600/*` at root) rather than in-tree staging paths
+(`drivers/staging/bes2600/*`), and at least one entry has corrupted
+mixed-prefix headers (`a/drivers/staging/bes2600/foo.c b/bes2600/foo.c`).
+Those series do NOT apply cleanly to the linux-pinetab2 baseline.
+
+Audit performed 2026-05-18 during ohm migration:
+- ka-promote ohm (using the per-series includes) produces a
+  172 644-byte cumulative touching 27 file paths, of which 11 are
+  bogus DKMS-style or mixed-prefix.
+- The hand-curated `0001-bes2600-besser-cumulative-series.patch` from
+  the working `danctnix-besser-pkgbuild` (boltzmann) is 148 149 bytes
+  touching 48 distinct in-tree staging files — and is what pkgrel=3
+  actually builds with.
+
+This single-file cumulative is staged here so the ohm migration can
+ship through the kernel-agent flow today without first reconstructing
+12 series-dirs. The proper per-series split is tracked separately —
+see kernel-agent issue (TBD) for the rewrite.
+
+## Provenance
+
+- Source file: `boltzmann:~/src/besser/marfrit-besser/danctnix-besser-pkgbuild/kernel/0001-bes2600-besser-cumulative-series.patch`
+- Reflects c5x driver state in `marfrit/bes2600-dkms-mobian` branch as
+  of 2026-05-08, applied against `drivers/staging/bes2600/` in-tree.
+- Series legend (A, B, C v3, F, G, D, E, C2, c5.x, c6.x, c7, H — NOT
+  alphabetical) per the danctnix-besser-pkgbuild changelog comments.