Update CLAUDE.md to reflect current state

Fix typecheck reference (ty not pyright), add content/ directory to layout, expand
Architecture section with combat, persistence, editor, content loading, and entity model.

.claude/CLAUDE.md

@@ -4,7 +4,7 @@ Telnet MUD engine built on telnetlib3. Python 3.12+, managed with uv.
 
 ## Commands
 
-- `just check` - lint (ruff --fix + format), typecheck (pyright), test (pytest)
+- `just check` - lint (ruff --fix + format), typecheck (ty), test (pytest)
 - `just lint` / `just typecheck` / `just test` - individual steps
 - `just run` - start the server (`python -m mudlib`)
 - `just debug` - start with debug logging
@@ -14,6 +14,7 @@ Telnet MUD engine built on telnetlib3. Python 3.12+, managed with uv.
 
 - `src/mudlib/` - the engine (commands, world, combat, render, store)
 - `tests/` - pytest tests
+- `content/` - content definitions (commands, combat moves) loaded at runtime
 - `worlds/` - world definition files (yaml/toml, version controlled)
 - `docs/` - project knowledge (see below)
 - `DREAMBOOK.md` - the vision, philosophy, wild ideas. not a spec
@@ -49,6 +50,10 @@ Update docs when:
 - world definitions live in data files, runtime state lives in memory
 - SQLite for persistence (player accounts, progress)
 - session mode stack filters what events reach the player (normal/combat/editor)
+- combat system: state machine with TOML-defined moves (attacks, defends, counters)
+- content loading: TOML definitions for commands and combat moves, loaded at startup
+- entity model: Entity base class, Player and Mob subclasses sharing common interface
+- editor mode: in-world text editor with syntax highlighting and search/replace
 
 ## Style