review: iteration-1 fixes across CI, bridge, VM harness, and docs

CI/pipeline:
- KERNEL_TARBALL passed as a YAML env literal '~' was never tilde-expanded
  and would have failed every hosted kernel-build dispatch; the path is now
  exported from the shell. Verified reproducible before the fix.
- Every job gets timeout-minutes; boot smoke uses timeout -k so a wedged
  qemu is SIGKILLed instead of holding the job.
- Tarball fetch + fail-closed sha256 verification deduplicated into
  build/fetch-kernel-tarball.sh (with curl retries), used by build-kernel.sh
  and both CI jobs. busybox fetch gains retries too.
- ccache layer for kernel-build (cache keyed on defconfig+patches) recovers
  the incremental-compile speed the ephemeral-runner move cost.
- build-kernel.sh now asserts every fragment option survived olddefconfig —
  merge_config -m pastes text and Kconfig silently drops unmet symbols.

rs485-bridge:
- pending-buffer cap (2x max RTU ADU) instead of unbounded growth;
  explicit accept-loop error handling with backoff instead of .flatten();
  per-arm inline bounds instead of the string-keyed lookup whose default
  would have mis-bounded a future get-input; control-socket cleanup errors
  surfaced; flag-shaped values rejected in arg parsing; doc example uses a
  private mktemp dir. Test timing margins widened for contended runners
  (gap 25->120ms, 60x margin on the split-frame test).

VM harness:
- stage-1/stage-2 boot scripts share one validated slot parser and one
  by-name populator (qemu/rootfs/etc/warden-lib.sh) — the duplicated
  parser had already diverged on validation; userdata/oem mount failures
  now fail fast with a greppable sentinel; udhcpc fallback keys off the
  interface actually having an address; switch_root applet guarded.
- boot-smoke delegates the qemu invocation to run.sh (machine shape lives
  in ONE place); run.sh port 0 disables a hostfwd.
- mkimage: unknown partition names fail at build time; DISK_END is a max,
  not last-entry; --state keys validated as filenames.
- portal-scenario: mock readiness is asserted (no silent fall-through),
  hostfwd port collisions retried, mount-failure sentinel fails fast.
- ui-shot: fixed sleeps replaced with bounded screendump polling; the
  repaint assertion is real and documented as such. qmp.py loses its
  module-global and gains argv validation.

Docs/scrub: bench-host paths and the site AP name removed from six more
port docs and two evidence tables; path-bearing build artifacts (.elf,
.map) untracked (the 154-byte firmware .bin is path-free and stays);
ADR-0003 marked visibility-superseded by ADR-0007; stale section
cross-reference fixed; flare-edge noted as private for outside readers;
stale root-level review report removed per the new workspace rule.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018HUayid7W5w7jBdb9Rrj1K

kernel/rv1106-enablement/build-m2.sh

@@ -8,7 +8,7 @@
 # Defaults match this workspace.
 set -euo pipefail
 
-FE="${FE:-<flare-edge>}"
+FE="${FE:?set FE to a flare-edge checkout path}"
 KTREE="${KTREE:-$FE/research/linux-6.18.46}"
 SDK_TC="${SDK_TC:-$FE/sdk/tools/linux/toolchain/arm-rockchip830-linux-uclibcgnueabihf/bin}"
 HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

kernel/rv1106-enablement/mailbox/scr1-echo/Makefile

@@ -1,7 +1,8 @@
 # HPMCU mailbox-echo firmware — bare-metal RV32IMC for the RV1106 SCR1 core.
 # Same xPack riscv-none-embed-gcc 10.2.0 + flags as the watchdog firmware.
 
-XPACK ?= <flare-edge>/sdk/sysdrv/source/mcu/prebuilts/gcc/linux-x86/riscv64/xpack-riscv-none-embed-gcc-10.2.0-1.2/bin
+# Point XPACK at the xpack riscv toolchain bin/ inside a flare-edge SDK checkout.
+XPACK ?= $(error set XPACK to the xpack-riscv-none-embed-gcc bin/ directory)
 CROSS ?= $(XPACK)/riscv-none-embed-
 
 CC      = $(CROSS)gcc

kernel/rv1106-enablement/rga/PORT-PLAN.md

@@ -295,7 +295,8 @@ implied by this kernel port.
   canvas + scanout mirror at 720×720×4B ≈ 2 MiB each); carry the same size unless a
   future accounting shows it's tight.
 - **Driver-parity table** (`../DRIVER-PARITY.md`) should move `RGA 2D (rga2)` from [ ] to
-  [wip]/[x] as these steps land, same convention as every other M-milestone row.
+  [wip]/[x] as these steps land, same convention as every other M-milestone row
+(the parity row already reads [x]).
 
 ## Sources