feat: initialize server structure and database schema

- Added initial server setup with Cargo.toml defining dependencies and project structure.
- Created build.rs for generating protobuf bindings and validating wire contracts.
- Established database schema with initial migration files for conversations, messages, and runs.
- Introduced tools and prompts for Cursor functionality, enhancing user interaction capabilities.

server/tests/support/fixtures.rs

@@ -0,0 +1,18 @@
+//! Provides isolated stores and canonical message fixtures for tests.
+#![allow(dead_code)]
+
+use cursor_server::{
+    model::{CanonicalMessage, Origin, Role},
+    store::Store,
+};
+
+pub async fn temp_store() -> (tempfile::TempDir, Store) {
+    let directory = tempfile::tempdir().unwrap();
+    let url = format!("sqlite://{}", directory.path().join("test.db").display());
+    let store = Store::connect(&url).await.unwrap();
+    (directory, store)
+}
+
+pub fn user(id: &str, text: &str) -> CanonicalMessage {
+    CanonicalMessage::text(id, Role::User, Origin::User, text)
+}