feat(examples): add content-generator example demonstrating Prompt Dependency Resolution

This example demonstrates the full workflow of generating InfoTech primers
using MarkiTect's Prompt Dependency Resolution infrastructure.

Features demonstrated:
- Artifact creation and storage with content-based addressing
- PromptTemplate with @{macro} resolution across multiple spaces
- Automatic dependency tracking and graph construction
- Provenance tracing from outputs back to inputs
- Visualization export (Mermaid format)
- Incremental execution with change detection

Files added:
- generate_primers.py: Complete working example
- README.md: Quick start guide and architecture overview
- TUTORIAL.md: Comprehensive 500+ line tutorial
- templates/generate-primer.md: Template with macros
- artifacts/topics/: ETL and Microservices topic definitions
- artifacts/guidelines/: Authoring rules and research protocol
- prepdr/: Original manual system (preserved for reference)

Example output:
- Generates 2 primers (ETL, Microservices)
- Creates 8 artifacts across 4 information spaces
- Records 8 dependency edges in SQLite database
- Exports dependency graph visualization

Run with: cd examples/content-generator && python generate_primers.py

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

examples/content-generator/artifacts/topics/microservices.md

@@ -0,0 +1,31 @@
+---
+id: topic-microservices
+name: Microservices
+artifact_type: content
+description: Topic definition for Microservices architecture
+version: 1.0.0
+tags:
+  - architecture
+  - distributed-systems
+  - topic
+---
+
+# Microservices Architecture
+
+An architectural style that structures an application as a collection of loosely coupled, independently deployable services, each implementing a specific business capability.
+
+Microservices represent a departure from monolithic architecture, emphasizing service autonomy, bounded contexts, and decentralized data management.
+
+**Key Characteristics:**
+- Independent deployment and scaling
+- Service-oriented API contracts (typically REST or gRPC)
+- Decentralized data management (database-per-service)
+- Polyglot persistence and technology diversity
+- Failure isolation and resilience patterns
+
+**Common Use Cases:**
+- Large-scale web applications
+- Cloud-native applications
+- Continuous delivery environments
+- Organizations requiring team autonomy
+- Systems requiring differential scaling