ci: gitea actions for the suites, the image and the APK

Four workflows, none of which existed:

* `tests.yml` — backend, desktop, `:core` and the web app's typecheck+build, in
  parallel. `:core` needs no Android SDK at all, because settings.gradle.kts
  leaves `:app` out when there is none; `:app`'s Robolectric suite therefore
  lives in the APK workflow, where the SDK is installed anyway. Nothing needs a
  running backend — the suites feed on committed fixtures, which is the whole
  reason they were written that way.
* `lint.yml` — ruff, which the repo had been configured for and never run.
* `docker.yml` — builds the image, *starts* it against SQLite and waits for
  /api/health before pushing, then publishes `:latest` and `:<short-sha>` to
  git.timka.su. A tag nobody can run is worse than no tag.
* `android-release.yml` — the release APK on every push to master, signed from
  secrets, with `apksigner verify --print-certs` reporting which key was really
  used and failing if it was the debug one.

Three things the repo needed before any of that could work:

`versionCode` was pinned at 1, so every APK looked like the same version to the
phone and would not install over its predecessor. It now comes from the run
number, with `versionName` from a property, both via one `setting()` helper that
reads a Gradle property or an environment variable.

The release build fell back to the *debug* signing key whenever the keystore was
missing — silently. That is a trap: the APK installs, looks fine, and can never
be upgraded by a properly signed build. `KADENCE_REQUIRE_SIGNING=1` makes that
case fail the build instead, and the release job sets it whenever a keystore
secret is present.

The compose files built an image with no name, so there was nothing to pull.
`image:` now names the registry tag while `up --build` still builds locally.

Also: `android/ci/install-sdk.sh` (idempotent, cacheable, and the one place that
knows `platforms;android-37.0` is spelled with the minor version), the runner as
a compose service with its config and a setup checklist, six make targets, and a
README section. No runner is registered yet — `make ci-runner` is step two of
that checklist.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

android/app/build.gradle.kts

@@ -19,6 +19,25 @@ plugins {
 val glyphAar = layout.projectDirectory.file("libs/glyph-matrix-sdk-2.0.aar").asFile
 val hasGlyphSdk = glyphAar.isFile
 
+/**
+ * One property or environment variable, whichever is set.
+ *
+ * CI passes these as environment variables and a developer puts them in
+ * `~/.gradle/gradle.properties`; neither should have to care which the build reads.
+ */
+fun setting(name: String): String? =
+    (project.findProperty(name) as String?) ?: System.getenv(name)
+
+/**
+ * Successive builds have to install over each other, so the code has to climb.
+ *
+ * It was pinned at 1, which meant every CI artifact looked like the same version to
+ * the phone. In CI this is the run number; locally it stays 1, because a developer
+ * installing over their own debug build does not care.
+ */
+val buildVersionCode = setting("KADENCE_VERSION_CODE")?.toIntOrNull() ?: 1
+val buildVersionName = setting("KADENCE_VERSION_NAME") ?: "0.1.0"
+
 android {
     namespace = "tech.kadence.android"
     compileSdk = libs.versions.compileSdk.get().toInt()
@@ -27,8 +46,8 @@ android {
         applicationId = "tech.kadence.android"
         minSdk = libs.versions.minSdk.get().toInt()
         targetSdk = libs.versions.targetSdk.get().toInt()
-        versionCode = 1
-        versionName = "1.0.0"
+        versionCode = buildVersionCode
+        versionName = buildVersionName
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
 
         buildConfigField("boolean", "HAS_GLYPH_SDK", hasGlyphSdk.toString())
@@ -53,16 +72,21 @@ android {
         // key: it still produces an installable APK for one's own phone, which is the
         // only distribution this app has.
         create("release") {
-            val storePath = (project.findProperty("KADENCE_KEYSTORE") as String?)
-                ?: System.getenv("KADENCE_KEYSTORE")
+            val storePath = setting("KADENCE_KEYSTORE")
             if (storePath != null && file(storePath).isFile) {
                 storeFile = file(storePath)
-                storePassword = (project.findProperty("KADENCE_KEYSTORE_PASSWORD") as String?)
-                    ?: System.getenv("KADENCE_KEYSTORE_PASSWORD")
-                keyAlias = (project.findProperty("KADENCE_KEY_ALIAS") as String?)
-                    ?: System.getenv("KADENCE_KEY_ALIAS") ?: "kadence"
-                keyPassword = (project.findProperty("KADENCE_KEY_PASSWORD") as String?)
-                    ?: System.getenv("KADENCE_KEY_PASSWORD")
+                storePassword = setting("KADENCE_KEYSTORE_PASSWORD")
+                keyAlias = setting("KADENCE_KEY_ALIAS") ?: "kadence"
+                keyPassword = setting("KADENCE_KEY_PASSWORD")
+            } else if (setting("KADENCE_REQUIRE_SIGNING") == "1") {
+                // Without this the fallback below quietly produces a *debug-signed*
+                // "release" APK: installable, apparently fine, and impossible to ship
+                // or to upgrade a real install with. A release job sets this so a
+                // missing or misnamed secret fails the build instead of the release.
+                throw GradleException(
+                    "KADENCE_REQUIRE_SIGNING is set but no keystore was found at " +
+                        "${storePath ?: "<KADENCE_KEYSTORE unset>"}",
+                )
             }
         }
     }