fix(build-gate): resolve commands by toolchain (#40)

core/kernel/AGENTS.md

@@ -20,6 +20,7 @@ CORREX kernel team. This is the integration point for all other `core/` modules.
 - `SubagentRunner` / `InSessionSubagentRunner` — runs sub-agent invocations within an active session.
 - `StaticAnalysisRunner` / `ProcessStaticAnalysisRunner` — runs static analysis tools and records results as events.
 - `LspDiagnosticsRunner` — injected pull-diagnostics seam; diagnostics are filtered to stage-written files, recorded, and enforced before build/review.
+- Execution gates infer the written stage's Node/JVM toolchain from its recorded file kinds and prefer the matching bound-profile command namespace, falling back to flat aliases.
 - Review→rework loops use the configured three-cycle default, then route accumulated notes to recovery once and fail if the fixed DoD still cannot be approved.
 - `StageCheckpointReconciler` — reconciles checkpoint state across stage transitions.
 - Capability-gated failures first retry in place when the stage holds the required tool; an unchanged-fingerprint gate-budget exhaustion routes to the recovery/intent-holder stage when one is available, so capability possession alone cannot cause a frozen owner loop to fail the workflow.

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/BuildGateToolchain.kt

@@ -0,0 +1,20 @@
+package com.correx.core.kernel.orchestration
+
+import com.correx.core.artifacts.kind.KindContractTable
+import com.correx.core.artifacts.kind.KindInference
+import com.correx.core.events.types.SessionId
+import com.correx.core.events.types.StageId
+
+/**
+ * Recovers the produced kind from this stage's recorded file manifest, then maps it to the
+ * toolchain-specific build command. File writes are event facts, so this remains replay-safe.
+ */
+internal fun SessionOrchestrator.stageProducedToolchain(
+    sessionId: SessionId,
+    stageId: StageId,
+): KindContractTable.Toolchain? = toolchainForPaths(stageWrittenPaths(sessionId, stageId))
+
+internal fun toolchainForPaths(paths: List<String>): KindContractTable.Toolchain? =
+    paths.asReversed().firstNotNullOfOrNull { path ->
+        KindInference.kindFor(path)?.let(KindContractTable::toolchainFor)
+    }

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/SessionOrchestratorGates2.kt

@@ -172,12 +172,14 @@ internal suspend fun SessionOrchestrator.runExecutionGate(
     val runner = staticAnalysisRunner
     val workspaceRoot = effectives.policy?.workspaceRoot
     if (runner == null || workspaceRoot == null) return StageExecutionResult.Success(emptyList())
-    val command = profileCommands[alias]
+    val toolchain = stageProducedToolchain(sessionId, stageId)?.profileKey
+    val command = expectation.commandFor(profileCommands, toolchain)
     if (command.isNullOrBlank()) {
         log.warn(
-            "[Orchestrator] stage {} needs a {} build gate but project profile has no '{}' " +
+            "[Orchestrator] stage {} needs a {} build gate but project profile has no '{}'{} " +
                 "command — skipping execution gate",
             stageId.value, expectation, alias,
+            toolchain?.let { " for toolchain '$it'" }.orEmpty(),
         )
         return StageExecutionResult.Success(emptyList())
     }

core/kernel/src/test/kotlin/com/correx/core/kernel/orchestration/BuildPrerequisiteDecisionTest.kt

@@ -1,5 +1,6 @@
 package com.correx.core.kernel.orchestration
 
+import com.correx.core.artifacts.kind.KindContractTable
 import com.correx.core.events.events.BuildPrerequisiteBootstrapAttemptedEvent
 import com.correx.core.events.events.EventMetadata
 import com.correx.core.events.events.EventPayload
@@ -17,6 +18,12 @@ import org.junit.jupiter.api.Test
 
 class BuildPrerequisiteDecisionTest {
 
+    @Test
+    fun `build gate toolchain follows the stage produced kind`() {
+        assertEquals(KindContractTable.Toolchain.NODE, toolchainForPaths(listOf("frontend/package.json")))
+        assertEquals(KindContractTable.Toolchain.JVM, toolchainForPaths(listOf("core/kernel/FooService.kt")))
+    }
+
     private val reason =
         "stage impl repeatedly referenced missing build prerequisite 'frontend/package.json' " +
             "(3 blocked attempts). Create or repair the project setup before continuing."