ci: retire the CircleCI job, GitHub Actions already supersedes it

emulator-build-test duplicated the integration job in .github/workflows,
and did the same work worse in three ways:

  * it cloned firmware `master` unconditionally, so any branch carrying a
    newer test harness ran against older firmware and failed for reasons the
    PR did not cause. That is why it has been red since build #673 while
    GitHub Actions stayed green on the same commits.
  * it set no timeouts, so a hung test produced no output until CircleCI
    killed the job at ten minutes -- reported as a timeout rather than a
    failing test, and discarding every result after the hang.
  * it also ran the firmware's C++ firmware-unit suite, which covers firmware
    code that no change in this repo can affect, and which the firmware repo
    already runs in its own CI.

The integration job builds from current firmware and bounds every step with
timeout-minutes, so a hang fails fast and names the test.

master has no required status checks, so removing the context does not block
any pull request. Also corrects the ci.yml header, which still described
pulling a published DockerHub image -- the job stopped doing that when it
started building from firmware.

Author: BitHighlander

.circleci/config.yml

@@ -1,14 +1,37 @@
 # KeepKey python-keepkey CI
 #
-# Pulls the published emulator image (kktech/kkemu) from DockerHub
-# and runs the full python integration test suite against it.
-#
 # Stage 1: GATE (seconds)
 #   └─ lint        basic Python syntax check
 #
 # Stage 2: TEST (gated by Stage 1)
-#   └─ integration full pytest suite against emulator
-
+#   └─ integration full pytest suite against the kktech/kkemu service image
+#
+# NOTE on what this job tests: it runs against a PUBLISHED emulator image, so
+# it tests the tests against whatever firmware that image was built from, not
+# against current firmware. Suites that gate on requires_firmware() therefore
+# SKIP rather than fail when the image is older than the feature -- the run
+# stays green while covering less than it appears to. Building the emulator
+# from current firmware in this job is the fix, and is what removes the
+# caveat; it is not done here.
+#
+# This is the ONLY CI for this repo. A CircleCI job (emulator-build-test) ran
+# alongside it and is retired here -- see .circleci/config.yml in history.
+# It is not worth keeping:
+#
+#   * It cloned firmware `master` unconditionally, so a branch carrying a newer
+#     test harness was always run against older firmware, and failed for a
+#     reason the pull request did not cause. It has been red since build #673
+#     while these workflows stayed green on the same commits.
+#   * It set no timeouts. A hung test produced no output until CircleCI killed
+#     the job at ten minutes, which reports a timeout rather than a failing
+#     test and discards every result after the hang.
+#   * Its own result collection was broken independently: the final step read
+#     test-reports/python-keepkey/status, which no longer exists, so the job
+#     could not report a verdict even when the suite completed.
+#   * It also ran the firmware's C++ firmware-unit suite, which covers firmware
+#     code that no change in THIS repo can affect, and which the firmware repo
+#     already runs in its own CI.
+#
 name: CI
 
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