Show the command a build actually runs on its artifact page

The artifact page read `branches.<branch>.buildCommand` from the primary
config only, so for a named build on a branch with its own config it showed
a command that build never ran — on vm4006 it showed the host config's
command for a build that ran the branch definition's `pitestFull`.

Resolving "what does this build run" now has one implementation,
`GitTallyConfig.buildSettings(branch, build)`: the branch entry with the
build definition's overrides applied last. The executor uses it, and the
page resolves it against the branch layer committed at the build's own
commit — the same inputs the executor had.

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

src/test/kotlin/de/hoennig/gittally/server/PermanentBranchRoutesTest.kt

@@ -8,6 +8,7 @@ import de.hoennig.gittally.build.BuildResultRepository
 import de.hoennig.gittally.build.BuildStatus
 import de.hoennig.gittally.config.ConfigLoader
 import de.hoennig.gittally.config.GitTallyConfig
+import de.hoennig.gittally.git.GitService
 import de.hoennig.gittally.metrics.SystemMetricsCollector
 import io.kotest.core.spec.style.FunSpec
 import io.mockk.clearMocks
@@ -52,6 +53,9 @@ class PermanentBranchRoutesTest : FunSpec() {
     @MockkBean
     lateinit var configLoader: ConfigLoader
 
+    @MockkBean
+    lateinit var gitService: GitService
+
     @MockkBean
     lateinit var metricsCollector: SystemMetricsCollector
 
@@ -81,11 +85,14 @@ class PermanentBranchRoutesTest : FunSpec() {
                 artifactStore,
                 controlTokens,
                 configLoader,
+                gitService,
                 metricsCollector,
                 branchListing,
                 branchPermalinks,
             )
             every { configLoader.load(any()) } returns GitTallyConfig()
+            every { configLoader.loadWithBranchLayer(any(), anyNullable()) } returns GitTallyConfig()
+            every { gitService.showFileAtCommit(any(), any(), any()) } returns null
             every { controlTokens.token() } returns "test-token"
             every { branchListing.branches(any()) } returns emptyList()
             every { branchPermalinks.latestGreenBuild("main") } returns greenBuild

src/test/kotlin/de/hoennig/gittally/server/UiControllerTest.kt

@@ -7,10 +7,13 @@ import de.hoennig.gittally.build.BuildResult
 import de.hoennig.gittally.build.BuildResultRepository
 import de.hoennig.gittally.build.BuildStatus
 import de.hoennig.gittally.build.RunningBuild
+import de.hoennig.gittally.config.BranchConfig
+import de.hoennig.gittally.config.BuildDefinition
 import de.hoennig.gittally.config.ConfigLoader
 import de.hoennig.gittally.config.GitTallyConfig
 import de.hoennig.gittally.config.GiteaConfig
 import de.hoennig.gittally.config.ServerConfig
+import de.hoennig.gittally.git.GitService
 import de.hoennig.gittally.metrics.MetricAggregate
 import de.hoennig.gittally.metrics.SystemMetrics
 import de.hoennig.gittally.metrics.SystemMetricsCollector
@@ -58,6 +61,9 @@ class UiControllerTest : FunSpec() {
     @MockkBean
     lateinit var configLoader: ConfigLoader
 
+    @MockkBean
+    lateinit var gitService: GitService
+
     @MockkBean
     lateinit var metricsCollector: SystemMetricsCollector
 
@@ -103,6 +109,7 @@ class UiControllerTest : FunSpec() {
                 artifactStore,
                 controlTokens,
                 configLoader,
+                gitService,
                 metricsCollector,
                 branchListing,
                 branchPermalinks,
@@ -112,6 +119,8 @@ class UiControllerTest : FunSpec() {
                     server = ServerConfig(impressumUrl = "https://example.org/imprint"),
                     gitea = GiteaConfig(baseUrl = "https://git.example.org", owner = "acme", repo = "widget"),
                 )
+            every { configLoader.loadWithBranchLayer(any(), anyNullable()) } returns GitTallyConfig()
+            every { gitService.showFileAtCommit(any(), any(), any()) } returns null
             every { controlTokens.token() } returns "test-token"
             every { repository.latestGreenFor(any()) } returns null
         }
@@ -264,6 +273,28 @@ class UiControllerTest : FunSpec() {
                 ).andExpect(content().string(not(containsString("reports/tests/test/packages/index.html"))))
         }
 
+        test("the artifact page shows the command of the build's own definition, not the plain branch command") {
+            val pitestResult =
+                successResult.copy(
+                    build = "pitest",
+                    name = "main@pitest",
+                    artifactKey = "main-pitest-key",
+                )
+            every { repository.history() } returns listOf(pitestResult)
+            every { artifactStore.artifactDir("main-pitest-key") } returns null
+            every { configLoader.loadWithBranchLayer(any(), anyNullable()) } returns
+                GitTallyConfig(
+                    branches = mapOf("default" to BranchConfig(buildCommand = "./gradlew quick-check")),
+                    buildDefinitions = mapOf("pitest" to BuildDefinition(buildCommand = "./gradlew pitestFull")),
+                )
+
+            mockMvc
+                .perform(get("/builds/main-pitest-key"))
+                .andExpect(status().isOk)
+                .andExpect(content().string(containsString("./gradlew pitestFull")))
+                .andExpect(content().string(not(containsString("./gradlew quick-check"))))
+        }
+
         test("artifact index links a single index-less report page as a directory, keeping the URL stable") {
             val artifactDir = Files.createDirectories(tempDir.resolve("main-abc123-key"))
             Files.createDirectories(artifactDir.resolve("reports/profile"))