docs: align with satware AG best practices

- Delete deprecated CLAUDE.md
- Create root-level AGENTS.md for AI assistant guidance
- Create SDD constitution in .specify/memory/constitution.md
- Align documentation with PARA structure (docs/product/project-brief.md, docs/tech/stack.md, docs/plans/)
- Add standardized YAML frontmatter to all documentation files
- Update README.md with saTway branding and structure

docs/product/project-brief.md

@@ -0,0 +1,29 @@
+---
+description: >-
+  High-level overview and purpose of the mw-pfeddersheim-workstation project.
+tags:
+  - project-brief
+  - infrastructure
+  - overview
+last_updated: '2026-03-09'
+---
+
+# mw-pfeddersheim-workstation Project Brief
+
+## Purpose
+This repository serves as the single source of truth for the configuration and lifecycle management of Michael Wegener's primary workstation at satware AG (Pfeddersheim location).
+
+## Goals
+1. **Reproducibility**: Ability to restore or rebuild the workstation environment using Ansible.
+2. **Reliability**: Automated maintenance and health checks.
+3. **Documentation**: Clear record of software stack, decision rationale (ADRs), and tribal knowledge.
+4. **Security**: Alignment with Zero-Trust principles and satware AG security standards.
+
+## Users
+- Primarily **Michael Wegener** (MW).
+- AI Assistants (Cline/Jane/Junie) for automated task execution and maintenance.
+
+## Lifecycle
+- **Provisioning**: Managed via Ansible playbooks.
+- **Maintenance**: Daily/Weekly tasks via `scripts/maintenance.sh`.
+- **Documentation**: Continuous updates as the system evolves.