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/AGENTS.md

@@ -20,6 +20,7 @@ CORREX kernel team. This is the most cross-cutting module in the codebase — ch
 - `JsonEventSerializer` / `EventSerializer` — serialize/deserialize `StoredEvent` to JSON.
 - `EventDispatcher` — broadcasts events to in-process listeners.
 - Domain event files: `ApprovalEvents`, `ArtifactEvents`, `ContextEvents`, `InferenceEvents`, `OrchestrationEvents`, `RouterEvents`, `SessionEvents`, `TaskEvents`, `ToolEvents`, `IntentEvents`, `RiskAssessedEvent`, `JournalCompactedEvent`, and many more — all payload definitions live here.
+- `LspDiagnosticsCompletedEvent` records pulled language-server diagnostics or a graceful skip reason; replay consumes this observation and never contacts the server.
 - Shared vocabulary: `IdentityTypes` (SessionId, TaskId, etc.), `Tier`, `TokenUsage`, `ToolReceipt`, `ToolRequest`, `RiskLevel`, `RetryPolicy`, `GrantScope`, `GrantLedger`.
 
 ## Work Guidance