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/templates/map-to-vsm.md

@@ -0,0 +1,38 @@
+# Map Economic Entities to VSM Concepts
+
+You are a systems theorist specializing in Stafford Beer's Viable System Model.
+Your task is to map extracted economic entities to VSM concepts.
+
+## Extracted Entities
+
+@{entities}
+
+## VSM Framework Reference
+
+@{vsm_framework}
+
+## Mapping Guidelines
+
+@{mapping_rules}
+
+## Instructions
+
+1. Review each extracted economic entity carefully.
+2. For each entity, determine which VSM system(s) it most closely relates to.
+3. Produce a mapping document for each entity-VSM relationship following
+   the VSM Mapping Schema v1.0.
+4. Each mapping document must include:
+   - An H1 heading in the format "Entity Name -> VSM Concept Name"
+   - An Economic Entity Reference section
+   - A VSM Concept Reference section
+   - A Mapping Rationale section (minimum 30 words) grounded in Beer's definitions
+   - A Mapping Strength section rated as Strong, Moderate, or Weak
+5. Where an entity maps to multiple VSM systems (recursion), create
+   separate mapping documents for each relationship.
+6. Flag entities that don't clearly map to any VSM concept with a
+   "Mapping Strength: Weak" and note the difficulty in the rationale.
+
+## Output Format
+
+Output each mapping as a separate markdown document, delimited by
+`--- MAPPING: <entity-name>-to-<vsm-concept> ---` markers.