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>

docker/volumes/db/migrations/006_replica_more_kinds.sql

@@ -0,0 +1,13 @@
+-- Migration 006: Extend the replicas.kind allowlist beyond 'dictionary'.
+-- Pre-allows the kinds we plan to ship in upcoming client releases so
+-- each adapter only needs a coordinated client + server-validation
+-- update, not another DB migration. The DB CHECK is belt-and-
+-- suspenders; src/libs/replicaSchemas.ts (KIND_ALLOWLIST) is the
+-- actual gate that decides which kinds the server accepts on push.
+
+ALTER TABLE public.replicas
+  DROP CONSTRAINT IF EXISTS replicas_kind_allowlist;
+
+ALTER TABLE public.replicas
+  ADD CONSTRAINT replicas_kind_allowlist
+  CHECK (kind IN ('dictionary', 'font', 'texture'));

docker/volumes/db/migrations/007_files_replica_grouping.sql

@@ -0,0 +1,15 @@
+-- Migration 007: Per-replica grouping for binaries in `files`.
+--
+-- Replica-kind binaries (custom dictionary mdx/mdd, font ttf/woff, ...)
+-- have no book_hash, so without these columns Storage Manager would
+-- lump every replica binary into one "no-book" bucket. Per-replica
+-- grouping needs the row to carry the replica's identity alongside
+-- file_key/size.
+
+ALTER TABLE public.files
+  ADD COLUMN IF NOT EXISTS replica_kind text NULL,
+  ADD COLUMN IF NOT EXISTS replica_id text NULL;
+
+-- Composite filter index for "list / count files by replica row".
+CREATE INDEX IF NOT EXISTS idx_files_replica_lookup
+  ON public.files (user_id, replica_kind, replica_id);