CI: one test binary per crate, nextest, line tables only (#3855)

* CI: line tables only for workspace crates, no debug info for dependencies

* CI: one integration-test binary per crate

Each crate's tests/*.rs files become modules of tests/it/main.rs. Files that change
process-wide state (Color Settings, the font database, installed plug-ins, the working
directory), the fuzz sweeps and the test targets the Affinity corpus workflow names stay
their own binaries.

* Docs: name the integration tests' new paths

* CI: xtask test with nextest and doctests, one wasm check, clippy --keep-going

cargo xtask ci runs the tests with cargo nextest (cargo test when it is not installed),
builds them with --lib --bins --tests, runs the doctests as their own step, and checks
the wasm crates in one cargo check --keep-going call.

crates/format/tests/it/links.rs

@@ -1,7 +1,5 @@
 //! Linked images in `.vectorcraft` files: their link details round-trip, and an image only linked
 //! images show is saved as its preview.
-// Integration tests: unwrapping and panicking on failure is fine here, unlike in shipped code (AGENTS.md › Robustness).
-#![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
 
 use std::sync::Arc;
 

crates/format/tests/it/main.rs

@@ -0,0 +1,9 @@
+//! Integration tests: one test binary for the crate, one module per area.
+// Unwrapping and panicking on failure is fine here, unlike in shipped code (AGENTS.md › Robustness).
+#![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
+
+mod links;
+mod native_v3;
+mod native_v4;
+mod save_options;
+mod streaming;

crates/format/tests/it/native_v3.rs

@@ -1,7 +1,5 @@
 //! `.vectorcraft` v3: compression, pruning unused images, keys from newer versions, colour
 //! profiles as a document field, saving for older versions and the embedded preview.
-// Integration tests: unwrapping and panicking on failure is fine here, unlike in shipped code (AGENTS.md › Robustness).
-#![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
 
 use std::io::Write as _;
 use std::sync::Arc;

crates/format/tests/it/native_v4.rs

@@ -1,7 +1,5 @@
 //! `.vectorcraft` v4: large data after the JSON (images, the PDF, profiles), small files still plain
 //! JSON, older versions inline, damaged offsets refused.
-// Integration tests: unwrapping and panicking on failure is fine here, unlike in shipped code (AGENTS.md › Robustness).
-#![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
 
 use std::sync::Arc;
 

crates/format/tests/it/save_options.rs

@@ -1,8 +1,6 @@
 //! The native save options of the file itself: Include Linked Files, embedded ICC profiles and the
 //! PDF a PDF-compatible file carries, each round-tripping (and ignored by readers that don't
 //! need them).
-// Integration tests: unwrapping and panicking on failure is fine here, unlike in shipped code (AGENTS.md › Robustness).
-#![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
 
 use std::sync::Arc;
 

crates/format/tests/it/streaming.rs

@@ -2,8 +2,6 @@
 //! before (the same JSON and data after it, unpacked; the same gzip header), files written the old
 //! way still open, entries are read whatever their order, and the limits apply per part of the
 //! file.
-// Integration tests: unwrapping and panicking on failure is fine here, unlike in shipped code (AGENTS.md › Robustness).
-#![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
 
 use std::collections::BTreeMap;
 use std::io::{Read, Write};