ci: add daily 15:00 PST kernel build

[Bjordis Collaku (bjordiscollaku)]

Adds a daily scheduled build so the resolute-qcom-devel integration branch gets
a fresh .deb uploaded to S3 every day at 15:00 PST (23:00 UTC).

What it does

A tiny scheduled dispatcher (daily-build.yml) that fires the existing
build-kernel.yml once a day with suite=resolute-qcom-devel. It builds nothing
itself - it just triggers the normal build, exactly like clicking "Run workflow".

• Schedule: cron: "0 23 * * *" = 15:00 PST.
• Builds: resolute-qcom-devel HEAD, uploaded to S3 (same path as a manual build).
• Also exposes workflow_dispatch so the daily build can be run on demand.

Why a dispatcher, not a schedule: on build-kernel.yml

A scheduled event carries no inputs, and build-kernel.yml's S3 upload is
gated on the runner input - which is empty under schedule, so a bare scheduled
run would build but upload nothing (and SUITE would fall back to resolute-qcom,
not the intended branch). Dispatching passes suite explicitly, so the scheduled
build behaves identically to a manual run. It also touches no existing file, so it
does not conflict with the in-flight build-kernel.yml rework in #25.

To change what it builds

Edit the single --field suite=... line - e.g. set resolute-qcom to build the
mirror instead of the integration branch.

[Bjordis Collaku (bjordiscollaku)]

Superseded: folded the daily build into #25 as a 2-line schedule: trigger on build-kernel.yml. Its reworked version handles a no-input scheduled run correctly (defaults to resolute-qcom-devel, null-safe S3 upload), so no separate dispatcher workflow is needed.