refactor: remove rust project

Removes rust directory containing the pubky library.
Updates build scripts to include local and remote options.
Updates README.md.
Adds simple-git as a dev dependency.

setup-rust.js

@@ -0,0 +1,62 @@
+const simpleGit = require('simple-git');
+const fs = require('fs').promises;
+const path = require('path');
+
+const rustDir = 'rust';
+const repoOwner = 'pubky';
+const repoName = 'pubky-core-mobile-sdk';
+const branch = 'main';
+const tempDir = 'temp';
+
+async function setupRustDirectory() {
+  try {
+    // Check if rust directory exists
+    const rustExists = await fs
+      .access(rustDir)
+      .then(() => true)
+      .catch(() => false);
+
+    if (!rustExists) {
+      console.log('Creating rust directory...');
+      await fs.mkdir(rustDir);
+
+      // Clone the repository directly into rust directory
+      const git = simpleGit();
+      await git.clone(
+        `https://github.com/${repoOwner}/${repoName}.git`,
+        tempDir,
+        ['--depth', '1', `--branch=${branch}`]
+      );
+
+      // Move all contents from temp directory to rust directory
+      const tempContents = await fs.readdir(path.join(tempDir));
+      await Promise.all(
+        tempContents.map(async (item) => {
+          if (item !== '.git') {
+            // Skip .git directory
+            const source = path.join(tempDir, item);
+            const dest = path.join(rustDir, item);
+            await fs.cp(source, dest, { recursive: true });
+          }
+        })
+      );
+
+      // Clean up temp directory
+      await fs.rm(tempDir, { recursive: true, force: true });
+      console.log('Rust directory setup completed successfully!');
+    } else {
+      console.log('Rust directory already exists, skipping setup...');
+    }
+  } catch (error) {
+    console.error('Error during rust directory setup:', error);
+    // Try to clean up temp directory if it exists
+    try {
+      await fs.rm(tempDir, { recursive: true, force: true });
+    } catch (cleanupError) {
+      console.error('Failed to clean up temporary directory:', cleanupError);
+    }
+    throw error; // Re-throw to be handled by the main try-catch
+  }
+}
+
+setupRustDirectory();