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/vsm-concept-schema-v1.0.md

@@ -0,0 +1,40 @@
+# VSM Concept Schema v1.0
+
+Schema definition for Viable System Model concept documents.
+
+## Required Sections
+
+### Definition
+A clear, concise definition of the VSM concept (20-200 words).
+
+### System Classification
+Which VSM system(s) this concept belongs to. Must reference at least one of:
+- System 1 (Operations)
+- System 2 (Coordination)
+- System 3 (Control)
+- System 3* (Audit)
+- System 4 (Intelligence)
+- System 5 (Policy)
+
+### Key Properties
+Bulleted list of essential properties or characteristics of this concept.
+
+### Relationships
+How this concept relates to other VSM concepts. List related concepts
+and the nature of the relationship (e.g., "regulates", "enables", "constrains").
+
+## Optional Sections
+
+### Examples
+Concrete examples illustrating the concept in organisational contexts.
+
+### Beer's Original Formulation
+Direct reference to how Stafford Beer originally described or defined
+this concept, with citation to the relevant work.
+
+## Validation Rules
+
+1. The document MUST contain an H1 heading with the concept name.
+2. The document MUST contain all four required sections: Definition, System Classification, Key Properties, Relationships.
+3. The Definition section MUST be between 20 and 200 words.
+4. The System Classification section MUST reference at least one VSM system (S1-S5 or S3*).