feat: implement diagnostic error messages in findConfig

- Added specific checks for .mex/ directory, git init, and scaffold completeness.
- Note: Existing tests in test/config.test.ts are currently failing due to the message change.
Waiting for confirmation to update test expectations.

Author: c4rl0s04

src/config.ts

@@ -9,13 +9,29 @@ import type { MexConfig } from "./types.js";
 export function findConfig(startDir?: string): MexConfig {
   const dir = startDir ?? process.cwd();
 
+  if (dir.split(/[\\/]/).includes(".mex")) {
+    throw new Error(
+      "You're inside the .mex/ directory. Run mex commands from your project root instead."
+    );
+  }
+
   // Try git root first, fall back to cwd if no git repo
-  const projectRoot = findProjectRoot(dir) ?? dir;
+  const gitRoot = findProjectRoot(dir);
+  const projectRoot = gitRoot ?? dir;
 
   const scaffoldRoot = findScaffoldRoot(projectRoot);
   if (!scaffoldRoot) {
+    if (!gitRoot) {
+      throw new Error("No git repository found. Initialize one first: git init");
+    }
+
+    const mexDir = resolve(projectRoot, ".mex");
+    if (existsSync(mexDir)) {
+      throw new Error("Scaffold directory exists but looks incomplete. Run: bash .mex/setup.sh");
+    }
+
     throw new Error(
-      `No scaffold found. Expected .mex/ directory or context/ directory in ${projectRoot}`
+      "No .mex/ scaffold found. Run: git clone https://github.com/theDakshJaitly/mex.git .mex && bash .mex/setup.sh"
     );
   }
 
@@ -37,7 +53,10 @@ function findProjectRoot(dir: string): string | null {
 function findScaffoldRoot(projectRoot: string): string | null {
   // Prefer .mex/ directory
   const mexDir = resolve(projectRoot, ".mex");
-  if (existsSync(mexDir)) return mexDir;
+  // Check if .mex exists and has the required setup file to consider it complete
+  if (existsSync(mexDir) && existsSync(resolve(mexDir, "setup.sh"))) {
+    return mexDir;
+  }
 
   // Fall back to context/ directory (current mex layout)
   const contextDir = resolve(projectRoot, "context");