Diagnostic dump in --smoke-tree-sitter handler

Round 6 (sibling-file approach) still failed on Windows. The smoke
handler reports the same pre-init-state-empty error even though the
build script copied tree-sitter.wasm next to the binary just before
the smoke step ran.

Add a diagnostic dump that prints process.execPath, dirname, the
computed siblingPath, existsSync result, the dir listing, env var,
and globalThis state. Whatever the next CI Windows run shows here is
what we need to fix.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: jahooma

cli/src/index.tsx

@@ -196,6 +196,30 @@ async function main(): Promise<void> {
       globalThis as { __CODEBUFF_TREE_SITTER_WASM_BINARY__?: Uint8Array }
     ).__CODEBUFF_TREE_SITTER_WASM_BINARY__
     const wasmPath = process.env.CODEBUFF_TREE_SITTER_WASM_PATH
+
+    // Diagnostic dump so CI logs (and bug reports) show exactly what
+    // the runtime saw when smoke fails. process.execPath, the
+    // siblingPath we expect, and what's actually in that directory.
+    const fs = await import('fs')
+    const path = await import('path')
+    const execDir = path.dirname(process.execPath)
+    const siblingPath = path.join(execDir, 'tree-sitter.wasm')
+    let dirListing: string[] = []
+    try {
+      dirListing = fs.readdirSync(execDir)
+    } catch (err) {
+      dirListing = [`<readdir failed: ${err instanceof Error ? err.message : err}>`]
+    }
+    console.error(
+      `[smoke diag] execPath=${process.execPath}\n` +
+        `[smoke diag] execDir=${execDir}\n` +
+        `[smoke diag] siblingPath=${siblingPath}\n` +
+        `[smoke diag] siblingExists=${fs.existsSync(siblingPath)}\n` +
+        `[smoke diag] dir contents (${dirListing.length}): ${dirListing.slice(0, 30).join(', ')}\n` +
+        `[smoke diag] env.CODEBUFF_TREE_SITTER_WASM_PATH=${wasmPath ?? '<unset>'}\n` +
+        `[smoke diag] globalThis wasmBinary bytes=${wasmBinary?.byteLength ?? 0}\n`,
+    )
+
     try {
       const { Parser } = await import('web-tree-sitter')
       if (wasmBinary) {
@@ -212,8 +236,9 @@ async function main(): Promise<void> {
         console.log(`tree-sitter smoke ok (locateFile, path=${wasmPath})`)
       } else {
         console.error(
-          'tree-sitter smoke FAIL: pre-init published neither globalThis bytes nor an env path. ' +
-            'The `with { type: \'file\' }` import returned falsy.',
+          'tree-sitter smoke FAIL: pre-init published neither globalThis bytes ' +
+            'nor an env path. Sibling tree-sitter.wasm not found relative to ' +
+            'process.execPath. See diag above for the actual paths.',
         )
         process.exit(1)
       }