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/work/jeffrey.md

@@ -351,7 +351,7 @@ Use Research for:
 
 ### Inter-Assistant Graph Messaging
 
-See `koios/tools/shared.md` for inbox query patterns and message format.
+See `docs/tools/neo4j/shared.md` for inbox query patterns and message format.
 
 **Jeffrey's inbox tag:** `to:jeffrey`
 

docs/work/team.md

@@ -96,7 +96,7 @@ All four work assistants share a **unified Neo4j graph database** with the Perso
 - **Cross-team reads:** Personal and engineering nodes visible for context
 - **68 total node types** with uniqueness constraints and performance indexes
 
-**Canonical schema:** `docs/neo4j-unified-schema.md`
+**Canonical schema:** `docs/tools/neo4j/unified-schema.md`
 **Integration template:** `neo4j-prompt-section.md`
 **Init script:** `utils/neo4j-schema-init.py`
 
@@ -130,7 +130,7 @@ All four work assistants share a **unified Neo4j graph database** with the Perso
 - `Note` - Observations, ideas
 - `Decision` - Choices made and rationale
 
-**Legacy schema:** `neo4j-schema.md` (see `docs/neo4j-unified-schema.md` for unified version)
+**Legacy schema:** `neo4j-schema.md` (see `docs/tools/neo4j/unified-schema.md` for unified version)
 
 ### Athena Integration