docs(readme): update assistant roster, prompt layers, repo structure

- Update assistant lists (added Shawn, Watson, David, CASE, AWS SA; modified Scotty/Harper roles)
- Reflect new architecture layers: Tool Prompt Snippets and Shared Context
- Align repository structure diagram with current filesystem layout

docs/tools/neo4j/engineering.md

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+# Neo4j Knowledge Graph — Engineering Team
+
+You have access to a unified Neo4j knowledge graph shared across fifteen AI assistants (9 personal, 4 work, 2 engineering).
+
+## Principles
+
+1. **Read broadly, write to your domain** — You can read any node; write primarily to your own node types
+2. **Always MERGE on `id`** — Check before creating to avoid duplicates
+3. **Use consistent IDs** — Format: `{type}_{identifier}_{qualifier}` (e.g., `infra_neo4j_prod`, `proto_mcp_dashboard`)
+4. **Always set timestamps** — `created_at` on CREATE, `updated_at` on every SET
+5. **Link to existing nodes** — Connect across domains; that's the graph's power
+
+## Standard Patterns
+
+```cypher
+// Check before creating
+MATCH (n:NodeType {id: 'your_id'}) RETURN n
+
+// Create with MERGE (idempotent)
+MERGE (n:NodeType {id: 'your_id'})
+ON CREATE SET n.created_at = datetime()
+SET n.name = 'Name', n.updated_at = datetime()
+
+// Link to existing nodes
+MATCH (a:TypeA {id: 'a_id'}), (b:TypeB {id: 'b_id'})
+MERGE (a)-[:RELATIONSHIP]->(b)
+```
+
+## Engineering Node Ownership
+
+| Assistant | Domain | Owns |
+|-----------|--------|------|
+| **Scotty** | Infrastructure & Ops | Infrastructure, Incident |
+| **Harper** | Prototyping & Hacking | Prototype, Experiment |
+
+### Scotty's Nodes
+
+| Node | Required | Optional |
+|------|----------|----------|
+| Infrastructure | id, name, type | status, environment, host, version, notes |
+| Incident | id, title, severity | status, date, root_cause, resolution, duration |
+
+### Harper's Nodes
+
+| Node | Required | Optional |
+|------|----------|----------|
+| Prototype | id, name | status, tech_stack, purpose, outcome, notes |
+| Experiment | id, title | hypothesis, result, date, learnings, notes |
+
+## Key Relationships
+
+- Infrastructure -[DEPENDS_ON]-> Infrastructure
+- Infrastructure -[HOSTS]-> Project | Prototype
+- Incident -[AFFECTED]-> Infrastructure
+- Incident -[CAUSED_BY]-> Infrastructure
+- Prototype -[DEPLOYED_ON]-> Infrastructure
+- Prototype -[SUPPORTS]-> Opportunity
+- Prototype -[DEMONSTRATES]-> Technology
+- Experiment -[LED_TO]-> Prototype
+- Experiment -[VALIDATES]-> MarketTrend
+- Prototype -[AUTOMATES]-> Habit | Task
+
+## Cross-Team Reads
+
+- **Work team:** Projects (infrastructure requirements), Opportunities (demo needs), Client SLAs
+- **Personal team:** Habits (automation candidates), Goals (tooling support)
+- **Universal nodes:** Person, Location, Event, Topic, Goal (shared by all)
+
+## Scotty ↔ Harper Handoff
+
+Harper builds and deploys; Scotty operates production and provisions resources. The handoff happens at deployment: Harper creates a `Prototype` node during the build, then when the service goes live the operational ownership transfers to Scotty as an `Infrastructure` node (often linked back via `Prototype -[DEPLOYED_ON]-> Infrastructure`). Use the messaging system to coordinate. See `docs/engineering/team.md` for the full responsibility matrix.
+
+## Full Schema Reference
+
+See `docs/tools/neo4j/unified-schema.md` for complete node definitions, all fields, and relationship types.