feat(skills): bulk-add root SKILL.md to 61 skills (native Agent Skills loadability)

Run the additive migration pass from SKILL-MIGRATION-GUIDE: generate a root SKILL.md
for every skill that lacked one, copied from its desktop/SKILL.md (or code/SKILL.md),
with name set to the directory name and description + body preserved verbatim.

- scripts/migrate_skill_root.py: the reusable, non-destructive migrator (dry-run default).
- 61 new root SKILL.md (desktop source for most; code/SKILL.md for 61/62/92).
- Untouched: 16/17/95 (already had root); desktop/ and code/ packaging left intact.
- All 64 root SKILL.md validate: frontmatter <=1024, kebab name, description present.

Still MANUAL (no SKILL.md source — commands/README only), need hand-authored root SKILL.md:
81-mac-optimizer, 90-reference-curator, 91-multi-agent-guide, 94-dintel-bootstrap.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

custom-skills/31-notion-organizer/SKILL.md

@@ -0,0 +1,95 @@
+---
+name: 31-notion-organizer
+description: |
+  Notion workspace manager for database optimization, property cleanup, and bulk operations.
+  Triggers: organize Notion, workspace cleanup, database schema, property standardization.
+---
+
+# Notion Organizer Skill
+
+## Purpose
+
+Specialized Notion workspace management capability for:
+- Database schema analysis and optimization
+- Property standardization and cleanup
+- Content restructuring and hierarchy optimization
+- Database merging and migration
+- Bulk operations with rate-limit compliance
+
+## Execution Strategy: Three-Tier Approach
+
+Always follow this priority order:
+
+### Tier 1: Notion MCP Tools (Primary)
+
+Use built-in MCP tools first. Available tools:
+
+| Tool | Purpose |
+|------|---------|
+| `mcp__notion__search` | Find pages/databases by keyword |
+| `mcp__notion__get-page` | Retrieve page content |
+| `mcp__notion__get-database` | Retrieve database schema |
+| `mcp__notion__create-page` | Create new pages |
+| `mcp__notion__update-page` | Modify page properties |
+| `mcp__notion__query-database` | Query database with filters |
+
+### Tier 2: Alternative Approaches (Fallback)
+
+If MCP tools insufficient:
+- Export/import via filesystem (user action required)
+- Memory tools for tracking state across sessions
+- Sequential thinking for complex planning
+
+### Tier 3: Python Scripts (Advanced)
+
+For bulk operations (50+ items):
+- Generate async Python scripts
+- Include rate limiting (3 req/sec max)
+- Provide requirements.txt
+- Always include dry-run option
+
+See `scripts/` directory for templates.
+
+## Operational Guidelines
+
+### Before Any Modification
+1. **Fetch first**: Always examine current structure before changes
+2. **Confirm destructive actions**: Get user approval for deletes/major restructures
+3. **Estimate impact**: For large operations, provide time/API call estimates
+4. **Backup reminder**: Remind about Notion version history
+
+### Rate Limits (Critical)
+- Maximum: 3 requests/second average
+- Use pagination (100 items max per request)
+- Implement exponential backoff on 429 errors
+
+### Communication
+- Korean for explanations (한국어로 설명)
+- English for code and technical terms
+- Structured before/after summaries
+
+## Quick Commands
+
+### Database Audit
+"Analyze [database name] structure and recommend optimizations"
+
+### Property Cleanup
+"Standardize property names in [database] to [convention]"
+
+### Bulk Move
+"Move all pages tagged [X] from [source] to [target]"
+
+### Schema Migration
+"Migrate data from [source database] to [target database]"
+
+## Workflow Patterns
+
+See `reference.md` for detailed workflow documentation.
+See `scripts/` for Python templates.
+
+## Limitations
+
+- Cannot access unshared databases/pages
+- Cannot modify workspace settings
+- Cannot recover permanently deleted content
+- Large operations (1000+ pages) require Python scripts