step 1: lock public api and pure core

AGENTS.md

@@ -2,15 +2,15 @@
 
 ## Current status
 
-Rebuild initialized.
+Step 1 complete.
 
 ## Completed steps
 
-None yet.
+Step 1 - Public API contract and pure core.
 
 ## Current step
 
-Step 1 - Public API contract and pure core.
+Step 2 - Thread-safe state, commands, overlays, and cache model.
 
 ## Design decisions
 
@@ -31,7 +31,13 @@ None yet.
 
 - Read `STEPS.md`, `FEATURES.md`, and `ARCHITECTURE.md`.
 - Created initial package, examples, tests, and agent-log structure.
+- Implemented public exports, exceptions, common types, tile provider registry, projection helpers, cache dataclasses, and GUI-dependent API stubs.
+- Added Step 1 tests for imports, providers, projection, and cache dataclasses.
+- Ran `uv run pytest`.
+- Ran `uv run ruff check .`.
+- Ran `uv run ruff format --check .`.
+- Ran `uv run pyright`.
 
 ## Next action
 
-Implement Step 1.
+Implement Step 2.