Add Docker setup, .env.example, updated .gitignore/CHANGELOG and ADRs 004-007 + arc42 template

CHANGELOG.md

@@ -2,4 +2,14 @@
 
 ## [Unreleased]
 
-- project structure and architecture documentation finalized (arc42 template, ADRs for module structure and tech stack).
+- Created ADR-006: Data Storage Strategy (SQLite vs PostgreSQL, admin configuration capabilities).
+- Created ADR-007: Redis Usage (use cases, TTL policies, fallback, and detailed admin interface capabilities to adjust configuration values such as rate limits and TTLs).
+- Updated TODO.md and DONE.md to reflect completion of data storage and caching ADRs.
+- Project documentation and foundational configuration phase completed. Next priority is implementation of the Playout Service.
+
+## [2026-08-02] - Architecture Foundation
+
+- Project structure and architecture documentation finalized (arc42 template fully populated, ADRs for overall design, module structure, and tech stack).
+- Consolidated ADR-001 (merged all previous drafts).
+- Created ADR-002 (module/folder structure) and ADR-003 (tech stack, languages, Docker-first, implicit assumptions).
+- Updated root README.md and `docs/architecture/README.md` with diagrams, quality goals, deployment view, and cross-references.