ci: always rebuild on schedule (drop builder-HEAD-only dedupe) (#98)

The preflight gate skipped scheduled runs whenever this repo's HEAD
matched the SHA recorded in the previous nightly release body. That key
ignores every upstream input the build actually depends on:
OpenIPC/firmware HEAD, the toolchain release, the kernel tarball, the
vendor osdrv packages, and individual buildroot package upstreams.
builder.sh re-clones OpenIPC/firmware fresh on every run, so those
inputs do move between nightlies even when this repo is quiet.

The concrete failure mode this caused: on 2026-05-26 OpenIPC/firmware
bumped its hisilicon-opensdk pin to b958db4, which contains the V4
mipi_rx vsync IRQ fix (openhisilicon PR #195, closes #194 — torn
frames / 'Timeout from venc channel 0' on hi3516ev200, gk7205v200,
gk7205v210, gk7205v300, hi3516ev300 hardware). The next builder
nightly (2026-05-27 07:00 UTC) ran with this repo unchanged since
2026-05-25, so preflight skipped the entire Firmware matrix. Field
cameras (verified: gk7205v210_lite_vixand-ivg-g4h at IP redacted,
running BUILD_ID nightly-20260526-ee40da8, srcversion
8EF923DF907C1F7F3C6898E — the pre-fix open_mipi_rx fingerprint from
PR #195's verification table) kept pulling the stale 'latest' release
asset and kept showing the regression after sysupgrade.

A cross-input dedupe key would be possible (firmware HEAD + toolchain
URL hash + ...) but enumerates every upstream this build pulls. Simpler
and correct: scheduled nightlies always build. workflow_dispatch is
unaffected — that path was already unconditional.

Co-authored-by: Dmitry Ilyin <zekccsripfwrocp-15689@yn.furvionx.com>

.github/workflows/master.yml

@@ -28,15 +28,16 @@ jobs:
           SHORT=$(git rev-parse --short HEAD)
           BUILD_ID="nightly-$(date -u +%Y%m%d)-${SHORT}"
           BUILT_AT=$(date -u +%Y-%m-%dT%H:%M:%SZ)
-          PREV=$(gh release view nightly --json body -q .body 2>/dev/null \
-                  | sed -n 's/^sha=//p' | head -1 || true)
-          if [ "${{ github.event_name }}" = "schedule" ] && [ "$PREV" = "$HEAD" ]; then
-            echo "Skip: HEAD ($HEAD) already published as the latest nightly."
-            echo "should_build=false" >> "$GITHUB_OUTPUT"
-          else
-            echo "Build: $BUILD_ID (event=${{ github.event_name }}, prev=$PREV)"
-            echo "should_build=true"  >> "$GITHUB_OUTPUT"
-          fi
+          # Nightly rebuilds unconditionally on schedule. builder.sh re-clones
+          # OpenIPC/firmware at HEAD on every run, so the relevant inputs are
+          # mostly outside this repo (firmware HEAD, toolchain release, kernel
+          # tarball, vendor osdrv, individual package upstreams). The previous
+          # gate skipped when only this repo's HEAD matched the last published
+          # nightly, which made upstream fixes (e.g. an openhisilicon mipi_rx
+          # regression fix that lands in firmware) invisible to users until
+          # something here happened to change. Always build on schedule.
+          echo "Build: $BUILD_ID (event=${{ github.event_name }})"
+          echo "should_build=true"  >> "$GITHUB_OUTPUT"
           echo "head_sha=$HEAD"      >> "$GITHUB_OUTPUT"
           echo "short_sha=$SHORT"    >> "$GITHUB_OUTPUT"
           echo "build_id=$BUILD_ID"  >> "$GITHUB_OUTPUT"