Migrate project artifacts to spec-kit format

- Move cross-cutting docs (personas, design system, implementation phases,
  Ideen.md) to .specify/memory/
- Move cross-cutting research and plans to .specify/memory/research/ and
  .specify/memory/plans/
- Extract 5 setup tasks from spec/setup-tasks.md into individual
  specs/001-005/spec.md files with spec-kit template format
- Extract 20 user stories from spec/userstories.md into individual
  specs/006-026/spec.md files with spec-kit template format
- Relocate feature-specific research and plan docs into specs/[feature]/
- Add spec-kit constitution, templates, scripts, and slash commands
- Slim down CLAUDE.md to Claude-Code-specific config, delegate principles
  to .specify/memory/constitution.md
- Update ralph.sh with stream-json output and per-iteration logging
- Delete old spec/ and docs/agents/ directories
- Gitignore Ralph iteration JSONL logs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.specify/templates/checklist-template.md

@@ -0,0 +1,40 @@
+# [CHECKLIST TYPE] Checklist: [FEATURE NAME]
+
+**Purpose**: [Brief description of what this checklist covers]
+**Created**: [DATE]
+**Feature**: [Link to spec.md or relevant documentation]
+
+**Note**: This checklist is generated by the `/speckit.checklist` command based on feature context and requirements.
+
+<!-- 
+  ============================================================================
+  IMPORTANT: The checklist items below are SAMPLE ITEMS for illustration only.
+  
+  The /speckit.checklist command MUST replace these with actual items based on:
+  - User's specific checklist request
+  - Feature requirements from spec.md
+  - Technical context from plan.md
+  - Implementation details from tasks.md
+  
+  DO NOT keep these sample items in the generated checklist file.
+  ============================================================================
+-->
+
+## [Category 1]
+
+- [ ] CHK001 First checklist item with clear action
+- [ ] CHK002 Second checklist item
+- [ ] CHK003 Third checklist item
+
+## [Category 2]
+
+- [ ] CHK004 Another category item
+- [ ] CHK005 Item with specific criteria
+- [ ] CHK006 Final item in this category
+
+## Notes
+
+- Check items off as completed: `[x]`
+- Add comments or findings inline
+- Link to relevant resources or documentation
+- Items are numbered sequentially for easy reference