style(simulation): fmt + clippy fixes for the measurement batch (gate bounce)

cargo fmt across the four new files; needless_range_loop x2 (enumerate /
iter_mut) and identity_op in hydrology_equilibrium.rs. cargo test was green
on the bounced push — lint-only fixes.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server/tests/wire_encoding_bench.rs

@@ -31,6 +31,7 @@
 use std::io::Cursor;
 use std::time::Instant;
 
+use serde::{Deserialize, Serialize};
 use settled_reach_server::atlas::believability::seed_to_u64;
 use settled_reach_server::atlas::district_profile::{
     derive_at_metres, BodyParams, ClimateConstants,
@@ -41,7 +42,6 @@ use settled_reach_server::atlas::heightmap::load_heightmap_png;
 use settled_reach_server::atlas::layer_proxy::REGION_TEMP_NONE_DC;
 use settled_reach_server::atlas::scale;
 use settled_reach_server::seed::SeedChain;
-use serde::{Deserialize, Serialize};
 
 /// The six wire arrays `DistrictWindowLayer` ships today (layer_proxy.rs),
 /// derived at full canvas size rather than the 4,096-cell window cap.
@@ -103,9 +103,8 @@ fn derive_canvas(
                 .map(|col| {
                     let wx = col as f64 * step_m;
                     let wy = row as f64 * step_m;
-                    let prof = derive_at_metres(
-                        seed, "GJ338Bd", params, ta, wx, wy, &climate, 0.0, &[],
-                    );
+                    let prof =
+                        derive_at_metres(seed, "GJ338Bd", params, ta, wx, wy, &climate, 0.0, &[]);
                     let temp_dc = match prof.temperature_c {
                         Some(t) => ((t * 10.0).round() as i32)
                             .clamp(i16::MIN as i32 + 1, i16::MAX as i32)
@@ -265,7 +264,13 @@ fn encode_bitpacked(canvas: &WireCanvas) -> (Vec<u8>, std::time::Duration, std::
     let vegetation = unpack_bits(&decoded.vegetation_bits, 3, n);
     let glaciation = unpack_bits(&decoded.glaciation_bits, 3, n);
     let dec_time = t1.elapsed();
-    std::hint::black_box((morphology.len(), elev_q.len(), moisture_q.len(), vegetation.len(), glaciation.len()));
+    std::hint::black_box((
+        morphology.len(),
+        elev_q.len(),
+        moisture_q.len(),
+        vegetation.len(),
+        glaciation.len(),
+    ));
     (bytes, enc_time, dec_time)
 }
 
@@ -404,7 +409,9 @@ fn png_encode_u8_plane(cols: u32, rows: u32, data: &[u8]) -> Vec<u8> {
 }
 
 fn png_decode_u8_plane(bytes: &[u8]) -> Vec<u8> {
-    let mut decoder = png::Decoder::new(Cursor::new(bytes)).read_info().expect("png read_info");
+    let mut decoder = png::Decoder::new(Cursor::new(bytes))
+        .read_info()
+        .expect("png read_info");
     let mut buf = vec![0u8; decoder.output_buffer_size()];
     let frame = decoder.next_frame(&mut buf).expect("png next_frame");
     buf[..frame.buffer_size()].to_vec()
@@ -436,7 +443,8 @@ fn encode_png(canvas: &WireCanvas) -> (Vec<u8>, std::time::Duration, std::time::
     let moisture_q_d = png_decode_u8_plane(&moisture_q_png);
     let vegetation_d = png_decode_u8_plane(&vegetation_png);
     let glaciation_d = png_decode_u8_plane(&glaciation_png);
-    let temp_dc_d: Vec<i16> = rmp_serde::from_slice(&temp_dc_bytes).expect("rmp_serde decode temp_dc");
+    let temp_dc_d: Vec<i16> =
+        rmp_serde::from_slice(&temp_dc_bytes).expect("rmp_serde decode temp_dc");
     let dec_time = t1.elapsed();
     std::hint::black_box((
         morphology_d.len(),
@@ -504,7 +512,8 @@ fn encode_png_of_bitpacked(
     let moisture_q_d = unpack_bits(&png_decode_u8_plane(&moisture_q_png), 7, n);
     let vegetation_d = unpack_bits(&png_decode_u8_plane(&vegetation_png), 3, n);
     let glaciation_d = unpack_bits(&png_decode_u8_plane(&glaciation_png), 3, n);
-    let temp_dc_d: Vec<i16> = rmp_serde::from_slice(&temp_dc_bytes).expect("rmp_serde decode temp_dc");
+    let temp_dc_d: Vec<i16> =
+        rmp_serde::from_slice(&temp_dc_bytes).expect("rmp_serde decode temp_dc");
     let dec_time = t1.elapsed();
     std::hint::black_box((
         morphology_d.len(),
@@ -559,14 +568,19 @@ fn run_canvas_report(
     rows: u32,
     label: &str,
 ) {
-    println!("\n=== T-1179 wire-size table: {label} = {} gridunits ===", cols as u64 * rows as u64);
+    println!(
+        "\n=== T-1179 wire-size table: {label} = {} gridunits ===",
+        cols as u64 * rows as u64
+    );
 
     let (canvas, derive_time) = derive_canvas(seed, params, ta, cols, rows);
     println!(
         "  derive: {:.2} ms ({} cells, {} Rayon threads available)\n",
         derive_time.as_secs_f64() * 1000.0,
         canvas.morphology.len(),
-        std::thread::available_parallelism().map(|n| n.get()).unwrap_or(0)
+        std::thread::available_parallelism()
+            .map(|n| n.get())
+            .unwrap_or(0)
     );
 
     let (rmp_bytes, rmp_enc, rmp_dec) = encode_rmp(&canvas);