Fix broken v2 bambulab schema refs, wire up v2 dispatchers, fix PrintJobStatus JSON mismatch

- v2/common/device/device.schema.json: stray backtick in bed $ref broke resolution
- v2/report/print/print.schema.json: ams $ref pointed at wrong path (missing ams/ subdir)
- v2/common/device/plate.schema.json: $id was copy-pasted from bed.schema.json
- Add v2/request.schema.json and v2/report.schema.json dispatchers - v2's leaf
  schemas were unreachable without them, same oneOf convention as v1
- Rewrite schemas/bambulab/README.md layout section, which still described
  v1's pre-rename paths and claimed v2 was removed
- PrintJob.status serialized as a raw i32 in Rust (prost stores proto3 enums
  as i32) while ts-types' TypeBox schema validates full enum name strings -
  add serde with= on the field so Rust JSON matches TS and protobuf's own
  canonical JSON enum mapping, plus a regression test

schemas/bambulab/v2/common/device/device.schema.json

@@ -6,7 +6,7 @@
   "type": "object",
   "properties": {
     "airduct": { "$ref": "./airduct.schema.json" },
-    "bed": { "$ref": "./bed.schema.json`" },
+    "bed": { "$ref": "./bed.schema.json" },
     "cam": { "$ref": "./cam.schema.json" },
     "ctc": { "$ref": "./ctc.schema.json" },
     "ext_tool": { "$ref": "./ext_tool.schema.json" },