Add comprehensive architecture documentation and related scripts

- Introduced multiple architecture documentation files covering building block view, runtime view, deployment view, concepts, architecture decisions, quality requirements, technical risks, glossary, UI and styling, testing, CI, and development setup.
- Migrated existing content from `architecture_overview.md` and `implementation_plan.md` into structured documentation.
- Created scripts for checking broken links in documentation and formatting Markdown files for consistency.
- Updated quickstart guide to provide clearer setup instructions and usage overview.
- Removed outdated MVP features and testing strategy documents to streamline documentation.

docs/architecture/README.md

@@ -0,0 +1,34 @@
+---
+title: "CalMiner Architecture Documentation"
+description: "arc42-based architecture documentation for the CalMiner project"
+---
+
+# Architecture documentation (arc42 mapping)
+
+This folder mirrors the arc42 chapter structure (adapted to Markdown).
+
+Files:
+
+- `01_introduction_and_goals.md`
+- `02_architecture_constraints.md`
+- `03_context_and_scope.md`
+- `04_solution_strategy.md`
+- `05_building_block_view.md`
+- `06_runtime_view.md`
+- `07_deployment_view.md`
+- `08_concepts.md`
+- `09_architecture_decisions.md`
+- `10_quality_requirements.md`
+- `11_technical_risks.md`
+- `12_glossary.md`
+
+Mapping notes:
+
+- `docs/architecture.md` and `docs/architecture_overview.md` contain high-level content that will be split into these chapter files.
+- `docs/quickstart.md` contains developer quickstart, migrations, testing and current status and will remain as a separate quickstart reference.
+
+Next steps:
+
+1. Move relevant sections from `docs/architecture.md` and `docs/architecture_overview.md` into the appropriate chapter files.
+2. Expand each chapter with diagrams, examples, and references to code (files and modules).
+3. Add links from the top-level `README.md` to `docs/architecture/README.md` and `docs/quickstart.md`.