feat: add Google code retrieval across desktop CLI and MCP

crates/searchi-core/src/code.rs

@@ -0,0 +1,52 @@
+//! Shared code-file classification for extraction and pre-ranking scope filters.
+use std::{path::Path, sync::OnceLock};
+
+pub const CODE_EXTENSIONS: &[&str] = &[
+    "rs", "py", "pyi", "js", "jsx", "mjs", "cjs", "ts", "tsx", "mts", "cts", "c", "h", "cpp", "cc",
+    "cxx", "hpp", "hxx", "hh", "go", "java", "kt", "kts", "cs", "swift", "m", "mm", "rb", "php",
+    "phtml", "scala", "sc", "sql", "sh", "bash", "zsh", "fish", "ps1", "psm1", "psd1", "bat",
+    "cmd", "lua", "r", "pl", "pm", "ex", "exs", "erl", "hrl", "hs", "lhs", "clj", "cljs", "cljc",
+    "dart", "vue", "svelte", "graphql", "gql", "tf", "tfvars", "proto", "zig", "vb", "vbs", "f",
+    "for", "f90", "f95", "f03", "pas", "d", "cmake",
+];
+const CODE_FILENAMES: &[&str] = &[
+    "makefile",
+    "gnumakefile",
+    "dockerfile",
+    "cmakelists.txt",
+    "justfile",
+];
+
+pub fn is_code_path(path: &Path) -> bool {
+    let extension = path
+        .extension()
+        .and_then(|value| value.to_str())
+        .unwrap_or("")
+        .to_ascii_lowercase();
+    let filename = path
+        .file_name()
+        .and_then(|value| value.to_str())
+        .unwrap_or("")
+        .to_ascii_lowercase();
+    CODE_EXTENSIONS.contains(&extension.as_str()) || CODE_FILENAMES.contains(&filename.as_str())
+}
+
+/// Static trusted SQL predicate for the shared internal `files f` alias. No
+/// caller-controlled query, path or extension is interpolated into this SQL.
+pub fn code_file_predicate() -> &'static str {
+    static SQL: OnceLock<String> = OnceLock::new();
+    SQL.get_or_init(|| {
+        let literals = |values: &[&str]| {
+            values
+                .iter()
+                .map(|value| format!("'{value}'"))
+                .collect::<Vec<_>>()
+                .join(",")
+        };
+        format!(
+            "(f.extension IN ({}) OR lower(f.filename) IN ({}))",
+            literals(CODE_EXTENSIONS),
+            literals(CODE_FILENAMES)
+        )
+    })
+}