feat(llm): add LLM integration module with OpenRouter and Claude Code adapters

Implements markitect/llm/ package with concrete LLMAdapter implementations:
- OpenRouterAdapter: HTTP via urllib with retry/backoff on 429/5xx
- ClaudeCodeAdapter: subprocess-based Claude CLI with stdin piping
- Factory pattern: create_adapter("openrouter") or create_adapter("claude-code")
- API key resolution chain: constructor > env var > project-root key file
- 42 unit tests, 2 integration tests (gated on API key / CLI availability)

Also adds the infospace-with-history example with Wealth of Nations VSM
analysis pipeline, templates, schemas, source chapters, and processed
output for chapters 1-2. process_chapters.py now supports --provider
and --model flags for automatic LLM-driven processing.

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

examples/infospace-with-history/schemas/chapter-analysis-schema-v1.0.md

@@ -0,0 +1,48 @@
+# Chapter Analysis Schema v1.0
+
+Schema definition for per-chapter VSM analysis documents.
+
+## Required Sections
+
+### Chapter Summary
+A concise summary of the chapter's main economic arguments and themes (50-300 words).
+
+### Entities Extracted
+A bulleted list of all economic entities extracted from this chapter.
+Each entry should include the entity name and a brief description.
+Must list at least one entity.
+
+### VSM Mappings
+A bulleted list of all entity-to-VSM mappings derived from this chapter.
+Each entry should include the entity name, the VSM concept, and the mapping strength.
+
+### VSM Coverage
+Assessment of which VSM systems are represented by the mappings from this chapter:
+- System 1 (Operations): covered/not covered
+- System 2 (Coordination): covered/not covered
+- System 3 (Control): covered/not covered
+- System 3* (Audit): covered/not covered
+- System 4 (Intelligence): covered/not covered
+- System 5 (Policy): covered/not covered
+
+Must assess coverage for all six system levels.
+
+### Gaps & Observations
+Identification of:
+- VSM systems not yet covered by entities from this chapter
+- Entities that were difficult to map
+- Notable patterns or themes in the mappings
+- Suggestions for further analysis
+
+## Optional Sections
+
+### Cross-chapter References
+References to entities or themes in other chapters that relate to
+findings in this chapter. Useful for building cross-chapter coherence.
+
+## Validation Rules
+
+1. The document MUST contain an H1 heading with the chapter analysis title.
+2. The document MUST contain all five required sections.
+3. The Entities Extracted section MUST list at least one entity.
+4. The VSM Coverage section MUST assess all six VSM system levels.