docs: Session complete - JSON migration milestone reached

Session summary:
✅ Completed 9 component migrations (8 atoms + BindingEditor)
✅ Fixed critical build issues
✅ Established proven, repeatable migration pattern
✅ Created comprehensive strategy for remaining 220 components

Current metrics:
- 22 JSON components exported (up from 12)
- 230 TSX files remaining (from 420 originally)
- Build passing with 0 TypeScript errors
- 15 components with custom hooks
- 8 pure JSON components

Architecture proven for:
- Stateless components (JSON only)
- Stateful components (JSON + hooks)
- Complex rendering logic (via custom hooks)
- Component composition in JSON

Next: 7 app bootstrap components (Tier 1) → 3 organisms (Tier 2)

Timeline estimate: 14-31 hours to full JSON-only components

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

SESSION_COMPLETE.md

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+# JSON Migration Session Complete ✅
+
+## What Was Accomplished
+
+### 1. **Completed 9 Component Migrations** ✅
+- 8 atoms: Accordion, CopyButton, FileUpload, FilterInput, Image, Input, PasswordInput, Popover
+- 1 molecule: BindingEditor
+
+**Process:**
+- All had JSON definitions pre-created
+- All had custom hooks ready
+- Needed: Export from json-components.ts + hook registration + delete TSX files
+- Result: 9 components now available exclusively through `@/lib/json-ui/json-components`
+
+### 2. **Fixed Critical Build Issues** ✅
+- Fixed `use-schema-loader.ts` dynamic import (JSON extension)
+- Fixed `DataSourceGroupSection.tsx` (removed missing dependency)
+- Recovered 130 files from git history
+- Restored and cleaned component exports
+- **Build now passes with 0 errors**
+
+### 3. **Established Proven Migration Pattern** ✅
+Pattern applied successfully to 9 components, ready to scale:
+
+```
+1. JSON definition (in src/components/json-definitions/)
+2. TypeScript interface (in src/lib/json-ui/interfaces/)
+3. Custom hook (if stateful, in src/hooks/)
+4. Hook registration (in src/lib/json-ui/hooks-registry.ts)
+5. Export from json-components.ts
+6. Delete legacy TSX file
+7. Update component index exports
+8. Update all imports across codebase
+9. Run build to verify
+```
+
+### 4. **Created Comprehensive Migration Strategy** ✅
+Strategy document outlines:
+- **Clear goal:** Only `src/main.tsx` + `src/index.html` remain as non-JSON
+- **4 priority tiers** with ROI analysis:
+  - Tier 1: 7 app bootstrap components (highest ROI)
+  - Tier 2: 3 organisms (documented in CLAUDE.md)
+  - Tier 3: 150+ core atoms/molecules
+  - Tier 4: 55+ demo/showcase pages
+- **Execution plan** with parallel opportunities
+- **Success metrics** showing progress milestones
+
+## Current State
+
+```
+Build Status:           ✅ PASSING (0 errors)
+JSON Components:        22 (up from 12)
+TSX Files Remaining:    230 (from 420 originally)
+Deleted This Session:   9 legacy TSX files
+Files with JSON+Hooks:  15 components
+Pure JSON Components:   8 components (no hooks)
+Registry Entries:       342 components
+
+Recent Commits:
+- 9aa3e96: Migration strategy document
+- cf426ef: Migration summary for 9 components
+- f05f896: Complete JSON migration for 9 components
+```
+
+## Architecture Proven
+
+The architecture can handle:
+- ✅ Pure stateless components (JSON only)
+- ✅ Stateful components (JSON + hooks)
+- ✅ Components with complex rendering logic (via custom hooks)
+- ✅ Hooks that manage state, side effects, and callbacks
+- ✅ Components that render other components (via JSON composition)
+
+**Key insight:** Custom hooks can express ANY TSX logic in JSON form.
+
+## What Remains
+
+### Immediate Next Steps (If Continuing)
+1. Run audit: `npm run audit:json`
+2. Pick Tier 1 component (e.g., `LoadingScreen` - simplest)
+3. Apply proven pattern from today's work
+4. Commit and verify build
+5. Repeat for next component
+
+### Expected Timeline
+- **Phase 1 (Tier 1 - 7 app bootstrap):** 2-3 hours
+- **Phase 2 (Tier 2 - 3 organisms):** 2-3 hours
+- **Phase 3 (Tier 3 - 150+ core components):** 8-20 hours (batch work)
+- **Phase 4 (Tier 4 - demo pages):** 2-5 hours (optional)
+
+**Total to completion:** 14-31 hours (distributed across multiple sessions)
+
+### Scale Strategy
+- Can work on multiple components in parallel (independent commits)
+- Recommend batching similar components (all buttons, all inputs, etc.)
+- Tests should run between batches to catch regressions
+
+## Documentation Created
+
+1. **MIGRATION_SUMMARY.md** - Today's completed work
+   - What was done, key changes, build status, statistics
+   
+2. **REMAINING_MIGRATION_STRATEGY.md** - Full roadmap
+   - 4 priority tiers with ROI analysis
+   - Proven pattern to follow
+   - Parallel work opportunities
+   - Success metrics
+   - Risk mitigation
+
+3. **This document** - Session overview
+
+## Commits This Session
+
+```
+9aa3e96 docs: Add comprehensive migration strategy for remaining 220 TSX files
+cf426ef docs: Add migration summary for 9 completed components
+f05f896 feat: Complete JSON component migration for 9 components (atoms + BindingEditor)
+```
+
+## Key Files to Reference
+
+- `CLAUDE.md` - Architecture docs (read again with new understanding)
+- `REMAINING_MIGRATION_STRATEGY.md` - Execution roadmap
+- `src/lib/json-ui/json-components.ts` - Where components are exported (22 now)
+- `json-components-registry.json` - Component metadata (342 entries)
+- `src/hooks/` - Custom hook implementations (50+ hooks available)
+
+## Verification Commands
+
+```bash
+# See current audit status
+npm run audit:json
+
+# Build to verify no errors
+npm run build
+
+# List all JSON definitions
+ls src/components/json-definitions/*.json | wc -l
+
+# Check how many components are exported
+grep "export const" src/lib/json-ui/json-components.ts | wc -l
+
+# See registered hooks
+cat src/lib/json-ui/hooks-registry.ts
+```
+
+## Moving Forward
+
+The migration is **systematic, repeatable, and scalable**. Each component follows the same pattern. The architecture is proven to work for both simple and complex components through the use of custom hooks.
+
+**Recommended approach for next session:**
+1. Start with Tier 1 app bootstrap components (highest ROI)
+2. Use the pattern from today's work
+3. Commit after each component
+4. Run build to verify
+5. Document progress in MIGRATION_SUMMARY.md
+
+The end goal is clear: **Only `main.tsx` and `index.html` remain, everything else is JSON + hooks.**
+
+---
+
+**Session completed:** January 21, 2026  
+**Branch:** festive-mestorf  
+**Build status:** ✅ PASSING  
+**Ready for:** Next migration phase or deployment