feat: initial Phase 1 implementation — core framework + Docker

- Data types (SManga, SChapter, Page, MangasPage, all Filter variants)
- Source interfaces (Source, CatalogueSource) with MD5-based ID generation matching Tachiyomi/Suwayomi
- HTTP client with per-host rate limiting, cookie jar, and 429 retry
- FlareSolverr v1 client (FLARESOLVERR_URL env)
- Generic GraphQL POST helper
- goquery HTML parser wrappers
- Source registry (panics on duplicate ID)
- Multi-stage Dockerfile (golang:1.26-alpine + distroless) and compose.yml (postgres, flaresolverr, app)

go.mod

@@ -0,0 +1,13 @@
+module goyomi
+
+go 1.26.2
+
+require (
+	github.com/PuerkitoBio/goquery v1.12.0
+	golang.org/x/time v0.15.0
+)
+
+require (
+	github.com/andybalholm/cascadia v1.3.3 // indirect
+	golang.org/x/net v0.52.0 // indirect
+)