feat: Complete Issue #3 - Schema Management with Enhanced Format Control

🔧 Schema Management System:
- schema-ingest: Store JSON schema files in database with metadata parsing
- schema-list: List all stored schemas with --format and --names-only options
- schema-get: Retrieve stored schemas to stdout or file
- schema-delete: Remove schemas with confirmation prompts
- Full database integration with schemas table

📊 Enhanced Format Control:
- MARKITECT_DEFAULT_FORMAT environment variable for global format defaults
- Consistent --format options across all CLI commands (table|json|yaml|simple)
- get_default_format() function with fallback logic for invalid values
- Applied format control to query, schema, metadata, list, and ast-stats commands

🛠️ Bug Fixes:
- Fixed ast-stats command empty output by adding 'simple' format handler
- Created missing schema_summary.py for schema visualization tests
- All 394 tests now passing

✨ Usability Improvements:
- Unified format handling across the entire CLI interface
- Environment-based configuration for user preferences
- Enhanced schema management workflow with comprehensive CRUD operations

🧪 Generated with [Claude Code](https://claude.ai/code)

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

Makefile

@@ -623,15 +623,37 @@ cli-get: $(VENV)/bin/activate
 	fi
 
 # Schema operations
-cli-generate-schema: $(VENV)/bin/activate
+cli-schema-generate: $(VENV)/bin/activate
 	@if [ -z "$(FILE)" ]; then \
 		echo "🔧 Generating schema from sample document..."; \
-		$(MARKITECT) generate-schema $(SAMPLE_DOC) --output-format json; \
+		$(MARKITECT) schema-generate $(SAMPLE_DOC) --format json; \
 	else \
 		echo "🔧 Generating schema from document: $(FILE)"; \
-		$(MARKITECT) generate-schema $(FILE) --output-format json; \
+		$(MARKITECT) schema-generate $(FILE) --format json; \
 	fi
 
+cli-schema-ingest: $(VENV)/bin/activate
+	@if [ -z "$(SCHEMA)" ]; then \
+		echo "❌ Usage: make cli-schema-ingest SCHEMA=schema.json"; \
+		echo "   Example: make cli-schema-ingest SCHEMA=my_schema.json"; \
+		exit 1; \
+	fi
+	@echo "📥 Ingesting schema: $(SCHEMA)"
+	@$(MARKITECT) schema-ingest $(SCHEMA)
+
+cli-schema-list: $(VENV)/bin/activate
+	@echo "📋 Listing stored schemas..."
+	@$(MARKITECT) schema-list --format $(OUTPUT_FORMAT)
+
+cli-schema-get: $(VENV)/bin/activate
+	@if [ -z "$(SCHEMA)" ]; then \
+		echo "❌ Usage: make cli-schema-get SCHEMA=schema_name"; \
+		echo "   Example: make cli-schema-get SCHEMA=my_schema.json"; \
+		exit 1; \
+	fi
+	@echo "📖 Retrieving schema: $(SCHEMA)"
+	@$(MARKITECT) schema-get $(SCHEMA)
+
 cli-validate: $(VENV)/bin/activate
 	@if [ -z "$(FILE)" ] || [ -z "$(SCHEMA)" ]; then \
 		echo "❌ Usage: make cli-validate FILE=document.md SCHEMA=schema.json"; \
@@ -763,7 +785,7 @@ cli-workflow-schema: $(VENV)/bin/activate
 	@$(MARKITECT) ingest $(FILE)
 	@echo ""
 	@echo "  Step 2: Generate schema"
-	@$(MARKITECT) generate-schema $(FILE) --output-format json > temp_schema.json
+	@$(MARKITECT) schema-generate $(FILE) --format json > temp_schema.json
 	@echo "  Schema saved to temp_schema.json"
 	@echo ""
 	@echo "  Step 3: Validate document against generated schema"
@@ -788,7 +810,10 @@ cli-help:
 	@echo "  cli-metadata [FILE=doc.md]   - Show document metadata"
 	@echo ""
 	@echo "Schema Operations:"
-	@echo "  cli-generate-schema [FILE=doc.md]        - Generate JSON schema"
+	@echo "  cli-schema-generate [FILE=doc.md]        - Generate JSON schema"
+	@echo "  cli-schema-ingest SCHEMA=schema.json     - Store schema in database"
+	@echo "  cli-schema-list [OUTPUT_FORMAT=table]   - List stored schemas"
+	@echo "  cli-schema-get SCHEMA=name               - Retrieve stored schema"
 	@echo "  cli-validate FILE=doc.md SCHEMA=schema.json - Validate document"
 	@echo "  cli-validate-detailed FILE=doc.md SCHEMA=schema.json - Detailed validation"
 	@echo "  cli-visualize-schema SCHEMA=schema.json  - Visualize schema (colorful)"
@@ -814,16 +839,18 @@ cli-help:
 	@echo ""
 	@echo "📋 Variables:"
 	@echo "  FILE         - Target markdown file (default: $(SAMPLE_DOC))"
-	@echo "  OUTPUT_FORMAT - Output format: table, json, yaml (default: $(OUTPUT_FORMAT))"
+	@echo "  OUTPUT_FORMAT - Output format: table, json, yaml, simple (default: $(OUTPUT_FORMAT))"
 	@echo "  SCHEMA       - JSON schema file"
 	@echo "  SQL          - SQL query string"
 	@echo "  QUERY        - JSONPath query expression"
 	@echo ""
 	@echo "💡 Examples:"
 	@echo "  make cli-ingest FILE=my_document.md"
+	@echo "  make cli-list OUTPUT_FORMAT=table"
+	@echo "  make cli-schema-list OUTPUT_FORMAT=simple"
 	@echo "  make cli-validate FILE=doc.md SCHEMA=doc_schema.json"
 	@echo "  make cli-ast-query FILE=doc.md QUERY='$.headings[*].text'"
 	@echo "  make cli-query SQL='SELECT title FROM metadata WHERE status=\"draft\"'"
 
 # Update .PHONY for CLI targets
-.PHONY: cli-ingest cli-status cli-list cli-get cli-generate-schema cli-validate cli-validate-detailed cli-ast-show cli-ast-stats cli-ast-query cli-metadata cli-query cli-schema-db cli-cache-info cli-cache-clean cli-cache-invalidate cli-visualize-schema cli-visualize-schema-ascii cli-workflow-basic cli-workflow-schema cli-help
+.PHONY: cli-ingest cli-status cli-list cli-get cli-schema-generate cli-schema-ingest cli-schema-list cli-schema-get cli-validate cli-validate-detailed cli-ast-show cli-ast-stats cli-ast-query cli-metadata cli-query cli-schema-db cli-cache-info cli-cache-clean cli-cache-invalidate cli-visualize-schema cli-visualize-schema-ascii cli-workflow-basic cli-workflow-schema cli-help