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)

TODO.md

@@ -0,0 +1,12 @@
+# tachiyomi-go — Master TODO
+
+Progress tracker across all implementation phases.
+Detailed checklists are in each phase doc under `docs/`.
+
+---
+
+- [x] **Phase 1 — Core Framework** → `docs/phase1-core-framework.md`
+- [ ] **Phase 2 — Database Layer** → `docs/phase2-database.md`
+- [ ] **Phase 3 — Base Source Implementations (68 bases)** → `docs/phase3-bases.md`
+- [ ] **Phase 4 — Standalone Sources (555 sources)** → `docs/phase4-standalone.md`
+- [ ] **Phase 5 — HTTP API** → `docs/phase5-api.md`