feat(api): upload queue with quota, tus intake, processing and import (M5.5)

- Migration 00008: upload_batches, upload_files, upload_quota.
- Quota reserved under a row lock when a batch is created; every status
  change goes through one transition that frees space in the same
  transaction. SHA-256 duplicates are rejected before any upload.
- tus 1.0.0 core (HEAD/PATCH) for the author only; offset is the real
  staging file size, data beyond the declared size is refused (ADR-015).
- Processing worker: ffprobe checks, SHA-256 verification, exact and
  Chromaprint duplicates against library and queue, metadata from tags
  or the dropped folder path, possible_duplicate on metadata match, and
  the target path from write_template reusing existing folder spelling.
- Import worker: edited tags written with ffmpeg stream copy, file
  written by storage-agent, point scan of the new file, imported status;
  idempotent and resumed after restart. Stale uploads expire after 24 h,
  orphan staging files are removed at startup.
- API: quota, precheck, batches, my uploads, withdraw, admin list,
  metadata edit, bulk review, retry and queue settings.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

services/api/internal/platform/config/config.go

@@ -62,6 +62,8 @@ type API struct {
 	GiteaRepo  string `env:"GITEA_REPO"`
 	GiteaToken string `env:"GITEA_TOKEN"`
 	UpdatesDir string `env:"UPDATES_DIR" envDefault:"/updates"`
+	// UploadsDir — staging очереди на добавление (локальный диск, общий со storage-agent на чтение).
+	UploadsDir string `env:"UPLOADS_DIR" envDefault:"/uploads"`
 }
 
 // StorageAgent — конфигурация внутреннего сервиса storage-agent.