fix(ysync): wire dialect == file dialect, uuid churn, drift noise

The Y.Doc is the source of truth for the FILE, but both live wires wrote
KiCad's CLIPBOARD dialect — a lossy, paste-oriented format. Every
difference was permanent, unfixable drift.

- pcbnew: serialize footprint blobs with CTL_FOR_BOARD, not CLIPBOARD_IO's
  CTL_FOR_CLIPBOARD, which emitted (version)(generator)(generator_version)
  inside every (footprint …). Keep (locked yes).
- eeschema: aForClipboard=false — clipboard mode collapsed every symbol's
  (instances … (path "/sheet")) to (path "").
- Re-supply (version) at PARSE time only (withFootprintVersion): the token
  is invalid file content but load-bearing on decode — without it the
  parser starts at m_requiredVersion=0 and stamps (hide yes) on every
  mandatory field.
- FOOTPRINT copy ctor: restore mandatory-field uuids (EDA_ITEM::operator=
  keeps the target's const m_Uuid, so Clone() rerolled all four).
- drift: classify order-only diffs as `reordered` — y-sexpr v2 reorders
  legitimately; excluded from counts, report-worthiness and dedupe hashes.
  Migration 0017.
- fpedit from eeschema: AsyncLoad()+BlockUntilLoaded() in initLibraryTree —
  FACE_PCB starts lazily there and never preloaded its libraries.

Guards: wire-vs-file round-trip tests (pcbnew + eeschema),
fpedit-from-eeschema (verified red without the fix), symedit-from-eeschema.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016p9kjdGBdcpwUSjJ3q5xg2

web/standalone/src/wasm/collab/drift-detect.ts

@@ -14,8 +14,9 @@
  * looks like a user save (no upload, no peer-tab dirty flag).
  */
 import {
-  docDelta,
+  compareSlots,
   type DriftReportBody,
+  driftDocDelta,
   fileToDoc,
   isEmptyKicadDelta,
   type Tool,
@@ -58,10 +59,17 @@ const DEFAULT_EVERY_N = 50;
 /** Reports per session cap — a real reconciler bug must not flood the backend. */
 const MAX_REPORTS_PER_SESSION = 20;
 
-/** djb2 over the drift-defining JSON — dedupe key, not a security hash. */
+/**
+ * djb2 over the drift-defining JSON — dedupe key, not a security hash.
+ *
+ * `diff.reordered` and `layoutReordered` are excluded on purpose: they are not
+ * drift, and v2's order churn would otherwise change the key on every pass and
+ * defeat the "report a stable divergence once" rule.
+ */
 function driftKey(body: DriftReportBody): string {
+  const { reordered: _reordered, ...diff } = body.diff;
   const canon = JSON.stringify({
-    diff: body.diff,
+    diff,
     layoutChanged: body.layoutChanged,
     metaChanged: body.metaChanged,
   });
@@ -132,10 +140,13 @@ export function startDriftDetection(opts: DriftDetectOptions): DriftDetector {
 
     const wasmDoc = fileToDoc(text);
     const ydocDoc = yToDoc(opts.doc);
-    const diff = docDelta(ydocDoc, wasmDoc);
-    // docDelta covers items only; flag layout/preamble divergence separately.
-    const layoutChanged =
-      JSON.stringify(ydocDoc.layout) !== JSON.stringify(wasmDoc.layout);
+    // Order-only differences go to `diff.reordered` / `layoutReordered`: y-sexpr
+    // v2 reorders legitimately, so they are noise, not divergence (kicad-delta.ts).
+    const diff = driftDocDelta(ydocDoc, wasmDoc);
+    // driftDocDelta covers items only; flag layout/preamble divergence separately.
+    const layoutRelation = compareSlots(ydocDoc.layout, wasmDoc.layout);
+    const layoutChanged = layoutRelation === "different";
+    const layoutReordered = layoutRelation === "reordered";
     const metaChanged = ydocDoc.root !== wasmDoc.root;
     if (isEmptyKicadDelta(diff) && !layoutChanged && !metaChanged) return null;
 
@@ -145,6 +156,7 @@ export function startDriftDetection(opts: DriftDetectOptions): DriftDetector {
       ydocDoc,
       diff,
       layoutChanged,
+      layoutReordered,
       metaChanged,
       // The docs above are version-blind (yToDoc normalizes v1/v2) — this is
       // the only signal of which storage encoding the Y.Doc actually used.
@@ -166,7 +178,9 @@ export function startDriftDetection(opts: DriftDetectOptions): DriftDetector {
       if (body) {
         log(
           `[drift] ${opts.targetPath}: +${body.diff.added.length} ~${body.diff.updated.length} -${body.diff.removed.length}` +
-            `${body.layoutChanged ? " layout" : ""}${body.metaChanged ? " meta" : ""}`,
+            `${body.diff.reordered.length ? ` (${body.diff.reordered.length} reordered, not drift)` : ""}` +
+            `${body.layoutChanged ? " layout" : ""}${body.layoutReordered ? " layout-reordered" : ""}` +
+            `${body.metaChanged ? " meta" : ""}`,
         );
         await reportDrift(opts.slug, body);
       }