feat: correx-managed model lifecycle slice 2 — per-stage model selection

StageConfig.modelId; InferenceRouter gains a backward-compatible model-aware
route() overload (default ignores modelId, so static routers and test fakes are
unaffected). New ManagedInferenceRouter (infra commons) resolves a target model
per stage (stage.modelId > capability match > default) and ensureLoaded()s it
before routing, returning the live managed provider — its id changes with the
resident model, so there is no stale health cache to invalidate on swap.
ModelManager.ensureLoaded default delegates to the idempotent load(). Main wires
the managed router on the [[models]] path; the static path keeps DefaultInferenceRouter.

Plan: docs/plans/2026-05-31-model-lifecycle-management.md (slice 2 of 5).

apps/server/src/main/kotlin/com/correx/apps/server/Main.kt

@@ -16,6 +16,7 @@ import com.correx.core.inference.CapabilityScore
 import com.correx.core.inference.DefaultInferenceRouter
 import com.correx.core.inference.InferenceProjector
 import com.correx.core.inference.InferenceRepository
+import com.correx.core.inference.InferenceRouter
 import com.correx.core.inference.ModelCapability
 import com.correx.core.kernel.orchestration.DefaultOrchestrationReducer
 import com.correx.core.kernel.orchestration.DefaultSessionOrchestrator
@@ -47,6 +48,7 @@ import com.correx.core.toolintent.rules.PathContainmentRule
 import com.correx.infrastructure.InfrastructureModule
 import com.correx.infrastructure.inference.DefaultProviderRegistry
 import com.correx.infrastructure.inference.FirstAvailableRoutingStrategy
+import com.correx.infrastructure.inference.commons.ManagedInferenceRouter
 import com.correx.core.inference.InferenceProvider
 import com.correx.infrastructure.inference.llama.cpp.LlamaCppInferenceProvider
 import com.correx.infrastructure.tools.FileEditConfig
@@ -78,10 +80,12 @@ fun main() {
     // Static path:  [[models]] absent  → legacy [[providers]] / env-var behavior
     val firstProvider: InferenceProvider
     val infraRegistry: DefaultProviderRegistry
+    val inferenceRouter: InferenceRouter
 
     if (correxConfig.models.isNotEmpty()) {
         val settings = correxConfig.modelsSettings
         val modelManager = InfrastructureModule.createModelManager(settings, eventStore, eventDispatcher)
+        val descriptors = correxConfig.models.map { InfrastructureModule.modelConfigToDescriptor(it) }
         val targetId = settings.defaultModel ?: correxConfig.models.first().id
         val targetModelConfig = correxConfig.models.firstOrNull { it.id == targetId }
             ?: correxConfig.models.first()
@@ -97,6 +101,9 @@ fun main() {
                 else -> { log.error("Unknown provider type: {}", providerConfig.type); null }
             }
         }.forEach { infraRegistry.register(it) }
+        // Managed router owns per-stage model selection: it ensures the resolved model is resident
+        // before routing (stage.modelId > capability match > default), evicting the prior model.
+        inferenceRouter = ManagedInferenceRouter(modelManager, descriptors, targetModelConfig.id)
         // Shutdown hook to kill the managed llama-server
         Runtime.getRuntime().addShutdownHook(Thread {
             log.info("Shutdown: unloading managed model '{}'", targetModelConfig.id)
@@ -110,6 +117,7 @@ fun main() {
         require(staticProviders.isNotEmpty()) { "At least one provider must be configured" }
         firstProvider = staticProviders.first()
         infraRegistry = InfrastructureModule.createProviderRegistry(staticProviders)
+        inferenceRouter = DefaultInferenceRouter(infraRegistry, FirstAvailableRoutingStrategy())
     }
 
     val modelId = firstProvider.id.value
@@ -161,7 +169,6 @@ fun main() {
         ),
     )
 
-    val inferenceRouter = DefaultInferenceRouter(infraRegistry, FirstAvailableRoutingStrategy())
     val engines = OrchestratorEngines(
         transitionResolver = DefaultTransitionResolver { condition, ctx -> condition.evaluate(ctx) },
         contextPackBuilder = DefaultContextPackBuilder(DefaultContextCompressor()),