Add perf triage for this week

Author: Mark-Simulacrum

draft/2025-07-02-this-week-in-rust.md

@@ -112,8 +112,17 @@ If you are an event organizer hoping to expand the reach of your event, please s
 <!-- Rust updates go here -->
 
 ### Rust Compiler Performance Triage
+Lots of changes this week with results dominated by the 1-5% improvements from
+[#142941](https://github.com/rust-lang/rust/pull/142941) across lots of primary
+benchmarks in the suite.
 
-<!-- Perf results go here -->
+Triage done by **@simulacrum**.
+Revision range: [42245d34..ad3b7257](https://perf.rust-lang.org/?start=42245d34d22ade32b3f276dcf74deb826841594c&end=ad3b7257615c28aaf8212a189ec032b8af75de51&absolute=false&stat=instructions%3Au)
+
+3 Regressions, 6 Improvements, 5 Mixed; 4 of them in rollups
+39 artifact comparisons made in total
+
+[Full report here](https://github.com/rust-lang/rustc-perf/blob/master/triage/2025/2025-06-30.md)
 
 ### [Approved RFCs](https://github.com/rust-lang/rfcs/commits/master)