fix(build): perbaiki referensi paket zesdex-gateway dan sinkronisasi versi nix

- Dockerfile & default.nix: ganti zesdex-backend -> zesdex-gateway (binary zesdex)
- flake.nix & default.nix: versi 1.13.0 -> 1.18.2
- Cargo.lock: sinkronkan versi workspace member (1.18.0 -> 1.18.2)
- perf(search): kurangi alokasi per-query di semantic search (Vec<String> -> Vec<&str>)
- chore(ci): drop cargo build release dari check job, tambah fmt check
- chore: tambah .dockerignore, perbaiki trailing newline .gitignore

apps/infrastructure/src/tools/semantic_search.rs

@@ -346,10 +346,7 @@ impl SymbolIndex {
         }
 
         let query_lower = query.to_lowercase();
-        let query_words: Vec<String> = query_lower
-            .split_whitespace()
-            .map(|s| s.to_string())
-            .collect();
+        let query_words: Vec<&str> = query_lower.split_whitespace().collect();
 
         let mut scored: Vec<(i32, &CodeSymbol)> = self
             .symbols
@@ -424,7 +421,7 @@ impl Default for SymbolIndex {
 }
 
 /// Score a symbol against a search query.
-fn score_symbol(sym: &CodeSymbol, query_lower: &str, query_words: &[String]) -> i32 {
+fn score_symbol(sym: &CodeSymbol, query_lower: &str, query_words: &[&str]) -> i32 {
     let name_lower = sym.name.to_lowercase();
     let mut score: i32 = 0;