feat(sync): cross-device custom font sync (#4077)

* refactor(sync): kind-agnostic replica primitives

Extract dict-only sync into shared primitives (registry, pull/apply
orchestrator, persist env, schema allowlist) so other kinds can plug
in. Companion changes: per-replica Storage Manager grouping,
useReplicaPull boot-race recovery, manifest=null reconciliation on
every boot pull, copyFile takes explicit srcBase + dstBase, settled-
event helpers, lenient webDownload Content-Length (R2/S3 signed URLs
commonly omit it), and generic "File" transfer toast copy any replica
kind can share.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat(sync): cross-device custom font sync

Plug the font replica adapter into the kind-agnostic primitives:
font store gains replica wiring, custom font import publishes the
replica row + queues a binary upload, and bootstrap registers the
font adapter and download-complete handler.

Includes legacy flat-path migration so pre-existing fonts sync
without re-import, full @font-face activation on auto-download
(load + mount the rule, mirroring manual import), and a fix to
createCustomFont so contentId / bundleDir / byteSize survive the
trip through addFont — otherwise import-time publish silently
no-oped on missing contentId.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/readest-app/src/services/nodeAppService.ts

@@ -236,10 +236,16 @@ export const nodeFileSystem: FileSystem = {
     return new File([buffer], fileName);
   },
 
-  async copyFile(srcPath: string, dstPath: string, base: BaseDir): Promise<void> {
-    const fullDst = await toAbsolute(this.resolvePath(dstPath, base));
+  async copyFile(
+    srcPath: string,
+    srcBase: BaseDir,
+    dstPath: string,
+    dstBase: BaseDir,
+  ): Promise<void> {
+    const fullSrc = await toAbsolute(this.resolvePath(srcPath, srcBase));
+    const fullDst = await toAbsolute(this.resolvePath(dstPath, dstBase));
     await fsp.mkdir(nodePath.dirname(fullDst), { recursive: true });
-    await fsp.copyFile(srcPath, fullDst);
+    await fsp.copyFile(fullSrc, fullDst);
   },
 
   async readFile(