wip(freestyle/acr): grounding & edit-tool fixes + ACR-compiler experiment

This branch's uncommitted WIP, committed together (entangled at file level).
Distinct pieces of work:

Freestyle QA fixes (this session):
- FileEditTool: pre-validate replace anchor in validateRequest — reject a
  missing/ambiguous target BEFORE the approval gate, mirroring read/write's
  file-not-found / read-before-write pre-checks. Shared not-found/ambiguous
  messages between validate and execute so they can't drift.
- PlanGrounder: add `scanned` flag; when no RepoMapComputedEvent was recorded,
  repoMapPaths is "unknown" not "empty workspace" — skip scope grounding
  (which proves a path ABSENT) so real paths (apps/server/**) aren't falsely
  rejected. Build-manifest check still runs.
- FreestyleDriver: wire scanned=(repoMap!=null); on plan rejection emit a
  session-terminal WorkflowFailedEvent so a rejected run reads FAILED, not the
  COMPLETED-lie (last verdict was the planning-phase WorkflowCompleted).
- ServerModule: resolve project-memory workspace root from the session's bound
  workspace (sessionWorkspaceRoot) instead of boot-static pm.repoRoot(), fixing
  the workspace-binding divergence (correx vs empty scratch dir). Retire tracked
  in Vikunja #266.
- LaunchRegistrationRaceTest: join registered jobs before asserting launchCount
  — computeIfAbsent returns the Job immediately but the fire-and-forget launch
  body lagged awaitAll (the 49-vs-50 flake).

ACR concept-compiler experiment (pre-existing WIP on this branch):
- ExecutionPlanCompiler/Model/PlanLinter, #264 needs-seam (sessionArtifacts),
  LSP diagnostics subsystem (LspDiagnosticEvents/Runner/Lsp4j), BootWorkspace,
  config surface, workflow prompts/schemas, orchestrator advance-don't-rerun.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/events/src/main/kotlin/com/correx/core/events/events/LspDiagnosticEvents.kt

@@ -0,0 +1,27 @@
+package com.correx.core.events.events
+
+import com.correx.core.events.types.SessionId
+import com.correx.core.events.types.StageId
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class LspDiagnostic(
+    val path: String,
+    val line: Int,
+    val character: Int,
+    val severity: String,
+    val code: String? = null,
+    val message: String,
+)
+
+/** Recorded LSP 3.17 pull-diagnostic observation; replay never re-queries a language server. */
+@Serializable
+@SerialName("LspDiagnosticsCompleted")
+data class LspDiagnosticsCompletedEvent(
+    val sessionId: SessionId,
+    val stageId: StageId,
+    val server: String?,
+    val diagnostics: List<LspDiagnostic>,
+    val skippedReason: String? = null,
+) : EventPayload

core/events/src/main/kotlin/com/correx/core/events/serialization/Serialization.kt

@@ -16,6 +16,7 @@ import com.correx.core.events.events.BriefEchoMismatchEvent
 import com.correx.core.events.events.BriefGroundingCheckedEvent
 import com.correx.core.events.events.ConceptPromotedEvent
 import com.correx.core.events.events.StaticAnalysisCompletedEvent
+import com.correx.core.events.events.LspDiagnosticsCompletedEvent
 import com.correx.core.events.events.ContractGateEvaluatedEvent
 import com.correx.core.events.events.PlanLintCompletedEvent
 import com.correx.core.events.events.ChatSessionStartedEvent
@@ -173,6 +174,7 @@ val eventModule = SerializersModule {
         subclass(BriefGroundingCheckedEvent::class)
         subclass(BriefEchoMismatchEvent::class)
         subclass(StaticAnalysisCompletedEvent::class)
+        subclass(LspDiagnosticsCompletedEvent::class)
         subclass(ContractGateEvaluatedEvent::class)
         subclass(PlanLintCompletedEvent::class)
         subclass(RiskAssessedEvent::class)

core/events/src/test/kotlin/com/correx/core/events/serialization/LspDiagnosticsCompletedEventSerializationTest.kt

@@ -0,0 +1,23 @@
+package com.correx.core.events.serialization
+
+import com.correx.core.events.events.LspDiagnostic
+import com.correx.core.events.events.LspDiagnosticsCompletedEvent
+import com.correx.core.events.types.SessionId
+import com.correx.core.events.types.StageId
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertIs
+
+class LspDiagnosticsCompletedEventSerializationTest {
+    @Test
+    fun `round-trips as polymorphic EventPayload`() {
+        val event = LspDiagnosticsCompletedEvent(
+            SessionId("s"), StageId("impl"), "tsserver",
+            listOf(LspDiagnostic("src/App.tsx", 1, 2, "error", "2322", "not assignable")),
+        )
+        val encoded = eventJson.encodeToString(com.correx.core.events.events.EventPayload.serializer(), event)
+        val decoded = eventJson.decodeFromString(com.correx.core.events.events.EventPayload.serializer(), encoded)
+        assertIs<LspDiagnosticsCompletedEvent>(decoded)
+        assertEquals("src/App.tsx", decoded.diagnostics.single().path)
+    }
+}