phsl / new-api

Backend
- Add GetBoundChannelsByModelsMap to batch-fetch bound channels via a single JOIN (Distinct), compatible with SQLite/MySQL/PostgreSQL
- Replace per-record enrichment with a single-pass enrichModels to avoid N+1 queries; compute unions for prefix/suffix/contains matches in memory
- Change Model.QuotaType to QuotaTypes []int and expose quota_types in responses
- Add GetModelQuotaTypes for cached O(1) lookups; exact models return a single-element array
- Sort quota_types for stable output order
- Remove unused code: GetModelByName, GetBoundChannels, GetBoundChannelsForModels, FindModelByNameWithRule, buildPrefixes, buildSuffixes
- Clean up redundant comments, keeping concise and readable code

Frontend
- Models table: switch to quota_types, render multiple billing modes ([0], [1], [0,1], future values supported)
- Pricing table: switch to quota_types; ratio display now checks quota_types.includes(0); array rendering for billing tags

Compatibility
- SQL uses standard JOIN/IN/Distinct; works across SQLite/MySQL/PostgreSQL
- Lint passes; no DB schema changes (quota_types is a JSON response field only)

Breaking Change
- API field renamed: quota_type -> quota_types (array). Update clients accordingly.