⚡ Bolt: [performance improvement]

.gitignore

@@ -40,3 +40,7 @@ security_best_practices_report.md
 # ForkTTY runtime
 /tmp/forktty.sock
 .worktrees/
+/zig-linux-x86_64-0.14.0
+/zig-linux-x86_64-0.14.0.tar.xz
+/zig-linux-x86_64-0.13.0
+/zig-linux-x86_64-0.13.0.tar.xz

.jules/bolt.md

@@ -0,0 +1,3 @@
+## 2026-08-14 - Fast-Path ASCII checks in Terminal Search
+**Learning:** Hoisting the computation of ASCII lowercase and uppercase values for the needle's first character outside the hot search loop and doing inline ASCII equality checks `h == first_lower || h == first_upper` eliminates function call overhead (`chars_eq_ignore_case`) for the vast majority of non-matching characters during massive terminal scrollback searches.
+**Action:** Always consider manually hoisting lightweight checks (like ASCII case bounds) out of hot iterator loops in Rust when dealing with millions of character iterations.

crates/forktty-ui-gtk/src/gtk_app/terminal_search.rs

@@ -75,11 +75,22 @@ fn for_each_char_match_start(
         return;
     }
     let first_needle = needle[0];
+    let first_is_ascii = first_needle.is_ascii();
+    let first_lower = first_needle.to_ascii_lowercase();
+    let first_upper = first_needle.to_ascii_uppercase();
+
     let mut index = 0;
     while index + needle.len() <= haystack.len() {
         // Fast-path: short-circuit the full substring check if the first character
         // doesn't match, avoiding iterator overhead in the common case.
-        if !chars_eq_ignore_case(haystack[index], first_needle) {
+        let h = haystack[index];
+        let first_match = if first_is_ascii && h.is_ascii() {
+            h == first_lower || h == first_upper
+        } else {
+            chars_eq_ignore_case(h, first_needle)
+        };
+
+        if !first_match {
             index += 1;
             continue;
         }