chore(brain): rename CLAUDE.md to schema.md for clarity

CLAUDE.md has a specific meaning in the Claude Code ecosystem (agent
instructions). The wiki schema for the ingestion pipeline should live
in schema.md to avoid confusion.

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

brain/schema.md

@@ -0,0 +1,154 @@
+# Brain Wiki Schema
+
+This document defines the three page types in the brain wiki.
+The LLM must follow this schema exactly when generating wiki pages.
+
+## Wikilink Format
+
+All cross-references use `[[slug|Display Text]]`.
+
+Rules:
+- slug = lowercase filename without .md, spaces → hyphens, strip all non-alphanumeric except hyphens
+- The `|` separator is REQUIRED — never use `[[Title]]` without a slug
+- Examples: `[[domain-driven-design|Domain Driven Design]]`, `[[ryan-singer|Ryan Singer]]`
+- Slugs must resolve to an existing file in the inventory, or a file you are creating in this response
+
+Slug generation examples:
+- "Domain Driven Design" → `domain-driven-design`
+- "It's Complicated" → `its-complicated`
+- "gRPC" → `grpc`
+- "GPT-4o" → `gpt-4o`
+
+## Domains
+
+Use one of: `ai-llm`, `software-engineering`, `product-strategy`, `finance-markets`,
+`personal`, `consulting`, `climate`, `infrastructure`, `security`
+
+---
+
+## Source Pages — wiki/sources/<slug>.md
+
+One page per ingested source. Books are NEVER split across multiple source pages — update the existing one.
+
+Required frontmatter:
+```yaml
+title: <exact title>
+type: article | pdf | book | video | note | project
+domain: <domain>
+date_ingested: YYYY-MM-DD
+last_updated: YYYY-MM-DD
+aliases:
+  - <exact title>
+```
+
+Body sections (in this order):
+
+### Summary
+2–3 sentences. Core argument or finding.
+
+### Key Claims
+Bulleted list. Paraphrase — no verbatim quotes or code.
+
+### Concepts Introduced or Reinforced
+Wikilinks to wiki/concepts/ ONLY. One per line.
+
+### Entities Mentioned
+Wikilinks to wiki/entities/ ONLY. One per line.
+
+### Open Questions Raised
+Gaps or follow-up questions from this source.
+
+For books only, also add:
+
+### Chapters
+One bullet per chapter with 1–2 sentence summary.
+
+### Argument Arc
+Overall narrative as it becomes clear across chapters.
+
+### Updates
+Dated entries appended on re-ingestion. NEVER rewrite — only append.
+
+---
+
+## Concept Pages — wiki/concepts/<slug>.md
+
+One page per idea, framework, methodology, or pattern.
+
+Required frontmatter:
+```yaml
+title: <concept name>
+domain: <domain>
+last_updated: YYYY-MM-DD
+aliases:
+  - <exact title>
+```
+
+Body sections (in this order):
+
+### Definition
+One-paragraph plain-language explanation.
+
+### Why It Matters
+Practical significance. Why should anyone care?
+
+### Related Concepts
+Wikilinks to wiki/concepts/ ONLY.
+
+### Related Entities
+Wikilinks to wiki/entities/ ONLY.
+
+### Sources
+Wikilinks to wiki/sources/ ONLY.
+
+### Evolving Notes
+Updated as new sources arrive. Append, do not rewrite.
+
+---
+
+## Entity Pages — wiki/entities/<slug>.md
+
+One page per person, tool, organisation, technology, or product.
+
+Required frontmatter:
+```yaml
+title: <name>
+type: person | company | tool | model | framework | technology
+domain: <domain>
+last_updated: YYYY-MM-DD
+aliases:
+  - <exact title>
+```
+
+Body sections (in this order):
+
+### Description
+One-line description.
+
+### Relevance
+Why this entity matters to this knowledge base.
+
+### Key Positions, Products, or Claims
+With dates where known.
+
+### Related Concepts
+Wikilinks to wiki/concepts/ ONLY.
+
+### Related Entities
+Wikilinks to wiki/entities/ ONLY.
+
+### Sources
+Wikilinks to wiki/sources/ ONLY.
+
+---
+
+## Non-Negotiable Rules
+
+1. Output ONLY a valid JSON array — no markdown fences, no prose before or after
+2. Each element: `{"path": "wiki/<type>/<slug>.md", "content": "...full markdown..."}`
+3. Slugs are kebab-case: lowercase, spaces→hyphens, strip special characters
+4. Every wikilink must be `[[slug|Display Text]]` — the pipe separator is required
+5. Dates always YYYY-MM-DD
+6. Never reproduce verbatim code — describe the pattern or technique
+7. Section links must match their section type (Related Concepts → concepts/ only, etc.)
+8. One source page per book — if inventory shows it exists, include it as an UPDATE