feat(sources): site kinds and capabilities (IA-2)

site.kind: pt / public_bt / rss_feed / torznab. Each kind declares the
acquisition modes it may support (search, list, rss, detail, login,
userinfo); a site's effective capabilities = kind ∩ site definition.
torznab only defines TorznabSiteConfig and cannot be added yet.

Migration 0055: generic_rss sites become rss_feed, the rest pt; feeds
without a site are grouped by host into new custom RSS source sites
(cursor window and conditional headers cleared so the next fetch writes
releases). User DB read-only dry-run: 0 orphan feeds.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/db/src/types.ts

@@ -239,6 +239,7 @@ export type ServerMappingMatchStatus = "matched" | "ambiguous" | "unmatched" | "
 export type SiteAdapter = "nexusphp" | "mteam_api" | "api" | "generic_rss";
 export type SiteHealthStatus = "unknown" | "healthy" | "degraded" | "failing" | "disabled";
 export type SiteCircuitState = "closed" | "open" | "half_open";
+export type SiteKind = "pt" | "public_bt" | "rss_feed" | "torznab";
 export type SiteAccountAuthKind = "cookie" | "passkey" | "api_key" | "password";
 export type SiteAccountStatus = "unknown" | "active" | "invalid" | "expired" | "challenge";
 export type SiteSnapshotKind = "periodic" | "backfill" | "live_search" | "manual";
@@ -1384,6 +1385,7 @@ export interface SiteTable {
   proxy: Generated<boolean>;
   deleted_at: Timestamptz | null;
   search_default: Generated<boolean>;
+  kind: Generated<SiteKind>;
 }
 
 export interface SiteAccountTable {