zeta2: Parse imports via Tree-sitter queries + improve zeta retrieval-stats (#39735)

Release Notes:

- N/A

---------

Co-authored-by: Max <max@zed.dev>
Co-authored-by: Agus <agus@zed.dev>
Co-authored-by: Oleksiy <oleksiy@zed.dev>

crates/languages/src/cpp/config.toml

@@ -17,3 +17,4 @@ brackets = [
 ]
 debuggers = ["CodeLLDB", "GDB"]
 documentation_comment = { start = "/*", prefix = "* ", end = "*/", tab_size = 1 }
+import_path_strip_regex = "^<|>$"

crates/languages/src/cpp/imports.scm

@@ -0,0 +1,5 @@
+(preproc_include
+    path: [
+        ((system_lib_string) @source @wildcard)
+        (string_literal (string_content) @source @wildcard)
+    ]) @import