Merge upstream/main (#2710 one test binary per crate, #2713) into round3a-integration

Conflicts:
- xtask/src/main.rs: upstream's runners (cargo test or nextest, no
  examples, doctests apart, one wasm `cargo check --keep-going`) with
  #2302's `ci --quick` on top: test_selected builds the same targets
  (--lib --bins --tests), the wasm check takes the changed crates in one
  call, the full test step is upstream's.
- apps/lightcraft/src/control_server.rs: upstream's `before` closure, with
  the batch's no-delay sockets kept.
- docs/parity-checklist.md: LR-BEHAV-ACCESS from main (tests/it path),
  LR-BEHAV-LOCALE / LR-BEHAV-LOCALIZE from the batch (Polish).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/files.rs

@@ -2809,7 +2809,7 @@ pub(crate) mod tests {
         let _ = std::fs::remove_dir_all(&dir);
     }
 
-    /// A Sony ARW of `model`: a 64 × 48 uncompressed 14-bit CFA strip in a SubIFD (as `crates/raw/tests/vendor_robust.rs`
+    /// A Sony ARW of `model`: a 64 × 48 uncompressed 14-bit CFA strip in a SubIFD (as `crates/raw/tests/it/vendor_robust.rs`
     /// lays it out) whose IFD carries the full-frame 16–35 mm distortion table (tag 0x7037).
     fn sony_arw(model: &str) -> Vec<u8> {
         use lightcraft_tiff::tags::{self as t, photometric};

crates/engine/src/tests_denoise.rs

@@ -1,7 +1,7 @@
 //! AI denoise through the engine: installing a model, making a photo's denoised picture in the background and for an
 //! export, the Amount slider mixing it in, and the cache. A tiny stand-in model (it halves every sample) takes the
 //! place of a real one, which is enough to see what the machinery does with its answer; how well real models denoise is
-//! measured separately (`crates/denoise/tests/real_model.rs`).
+//! measured separately (`crates/denoise/tests/it/real_model.rs`).
 
 use std::path::{Path, PathBuf};
 use std::sync::Arc;

crates/engine/tests/it/denoise_cpu.rs

@@ -1,10 +1,9 @@
 //! Opt-in same-machine denoise model-stage benchmark on one public Bayer raw.
 //! LC_DENOISE_MODEL=<onnx> LC_DENOISE_RAW=<CC0 corpus/raw> cargo test --release
-//! -p lightcraft-engine --features denoise --test denoise_cpu -- --ignored --nocapture
+//! -p lightcraft-engine --features denoise --test it denoise_cpu:: -- --ignored --nocapture
 //! LC_DENOISE_ONLY selects a file (default arw-sony-a7m3-compressed.arw).
 //! The whole model stage includes packing, scale/clip protection, blending and normalization;
 //! file decode, model loading and GPU setup are outside the timer. It uses the application's tile pool convention.
-#![cfg(feature = "denoise")]
 
 use lightcraft_denoise::{
     TileRunner,

crates/engine/tests/it/denoise_real.rs

@@ -4,12 +4,11 @@
 //!
 //! ```text
 //! LC_DENOISE_MODEL=<model_bayer.onnx> LC_DENOISE_RAW=<folder with raw files> \
-//!   cargo test --release -p lightcraft-engine --features denoise --test denoise_real -- --ignored --nocapture
+//!   cargo test --release -p lightcraft-engine --features denoise --test it denoise_real:: -- --ignored --nocapture
 //! ```
 //!
 //! `LC_DENOISE_RAW` is a folder of CC0 raw files (`cargo xtask corpus --download` → `corpus/raw`); every file in it is
 //! tried. Optional: `LC_DENOISE_ONLY` (a file name to try alone), `LC_DENOISE_RUN_ON=cpu|gpu|auto` (where the model runs; `cpu` to compare with the card).
-#![cfg(feature = "denoise")]
 
 use std::path::{Path, PathBuf};
 use std::time::{Duration, Instant};

crates/engine/tests/it/main.rs

@@ -0,0 +1,7 @@
+//! The integration tests, one module per file, linked into one test binary.
+
+#[cfg(feature = "denoise")]
+mod denoise_cpu;
+#[cfg(feature = "denoise")]
+mod denoise_real;
+mod preview_read;

crates/engine/tests/it/preview_read.rs

@@ -2,7 +2,7 @@
 //! network share, which is where reading only the header instead of the whole raw matters:
 //!
 //!   LC_PREVIEW_RAW="/run/user/1000/gvfs/smb-share:.../DSCF0001.RAF" \
-//!     cargo test --release -p lightcraft-engine --test preview_read -- --ignored --nocapture
+//!     cargo test --release -p lightcraft-engine --test it preview_read:: -- --ignored --nocapture
 //!
 //! It reports what the preview cost and fails when the read is not the small part of the file the
 //! header path promises. Skipped without `LC_PREVIEW_RAW` (there is no committed raw fixture: media