Attachment that grows past maxAttachmentSizeKB is silently overwritten by the stale remote copy

[Mokson]

Version: plugin 2.1.1, server 0.3.0

Summary
When a local attachment grows beyond maxAttachmentSizeKB, the next authoritative reconcile replaces it on disk with the older remote bytes. No conflict artifact, no Notice.

Path (tag 2.1.1)

1. src/sync/blobSync.ts:661 - the reconcile size filter drops the oversized file from diskBlobs, but its path remains in crdtBlobPaths.
2. src/sync/blobSync.ts:704-713 - the "CRDT blob not on disk" branch schedules a download for a path that is on disk.
3. src/sync/blobSync.ts:876 - processUpload skips the file by size, so the newer local bytes never reach the server.
4. src/sync/blobSync.ts:1234 - processDownload sees diskHash !== item.hash, re-hashes, finds no change during the download, and takes the overwrite-existing branch via modifyBinary.

Related

• src/runtime/capabilityUpdateService.ts:505-514 clamps maxAttachmentSizeKB down to the server's maxBlobUploadBytes and persists it with only a debug log, so a server-side cap reduction pushes every attachment above the new cap into this path.
• Oversized attachments are not counted in reconcile's skipped and produce no Notice (unlike oversized notes at reconciliationController.ts:552), which is why the overwrite is invisible with debug off.

Repro

1. Two devices in sync, attachment a.png at 1 MB.
2. On device A, replace a.png with a 12 MB file (cap 10240 KB).
3. Restart Obsidian on device A (or trigger a reconnect reconcile).
4. a.png on device A is back to the 1 MB remote copy. The 12 MB file is gone.

Expected
Oversized local attachments are excluded from download as well as upload, or preserved via a conflict artifact, and surfaced with a Notice like oversized notes.

Tests
tests/client/blob-download-conflicts.ts covers race and mismatch quarantine; nothing exercises the size-limit path.