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>

docs/AGENTS.md

@@ -14,7 +14,7 @@ Maintained alongside the features they describe. Any agent shipping a significan
 - `decisions/` — ADRs (adr-NNNN-*.md). Append-only. Never delete or retroactively alter a decided ADR; write a superseding one instead.
 - `qa/` — QA run plans (QA-*.md). Each maps to a shipped feature or an explicitly pending controlled audition. `TEMPLATE.md` is the canonical shape. `ENV.md` describes the required live environment. `README.md` explains the QA process.
 - `specs/` — feature specs by date-slug. Inputs for planned or in-flight work.
-- `schemas/` — canonical JSON schemas for structured outputs (analysis, brief_echo, design, execution_plan, impl_plan). Shared across the router and validator.
+- `schemas/` — canonical JSON schemas for structured outputs (analysis, discovery brief, DoD, brief_echo, design, execution_plan, impl_plan). Shared across the router and validator.
 - `epics/`, `modules/`, `diagrams/`, `design/`, `reviews/`, `visual/` — supporting reference material.
 
 **⚠️ STALE / DO NOT TRUST FOR STATUS:**