CI-01: this repository's first automated check

Before this commit `admin/goodwe-addon` had no `.gitea/workflows/` directory at
all. Eight runnable test files - `test_loop.py` alone drives the real
`run_control()` for 93 s of wall clock - and not one of them had ever been run
by a machine. Every merge here was a human reading a diff, and the product
owner's requirement that a green CI gate a merge could not be met on a
repository with no CI to be green.

One job, `unit`, with no `paths:` filter, so it reports on every PR and can
therefore be a REQUIRED status check: Gitea leaves a required context it never
receives pending forever, which is the failure mode on the other side of this
ticket. Concurrency is scoped per PR from the start rather than to a bare group
name - the bare name is what let the infra repo's run 521 be superseded while
still pending, so its four jobs concluded `cancelled` with `started_at` at the
Unix epoch and its PR merged on no evidence at all.

The tests run in `.gitea/ci/Dockerfile`: `alpine:3` plus `py3-aiohttp` and
`py3-paho-mqtt` from apk, matching goodwe_controller/Dockerfile exactly, because
pip would install glibc wheels of a library the shipped image gets from Alpine.
The runner itself cannot host them - bare python3, no aiohttp, no pip - and
mutating a shared long-lived runner with `apk add` is invisible to anyone
reading this repo.

Two things measured while building it and recorded in the file rather than
learned again: the checkout must sit two levels below the mount root or
test_freeze.py's `find_hwsim()` dies on `IndexError: 1` before its first
assertion, and test_freeze's hwsim section is silently absent here because
admin/goodwe is private - so its PASS is a weaker claim than it looks, and the
file says so.

Verified green on release/1.0 content before this workflow was written: 8 of 8
files pass, ~4 minutes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015VXjA3LWccN1rJsk3okyPC

.gitattributes

@@ -8,3 +8,11 @@
 * text=auto eol=lf
 *.png binary
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+
+# `.gitea/workflows/*.yml` steps embed shell heredocs; a `\r` on the terminator
+# line means the heredoc never closes and the job fails on a syntax error that is
+# invisible in the diff. A Windows checkout with core.autocrlf=true would
+# reintroduce it on the next edit. CI-01.
+*.yml  text eol=lf
+*.yaml text eol=lf
+Dockerfile text eol=lf