Releases offer plain programs; the licences are built in

Release assets are now the programs themselves: SolveCraft and solvecraft-cli .exe for Windows,
plain Linux binaries plus the AppImage, a macOS .dmg (SolveCraft.app with an Applications link) and
the universal CLI binary; only the web app stays a zip. The notes template takes {tag}, says to
chmod +x on Linux and macOS, and GitHub adds the change list.

Since no LICENSE or NOTICE file rides along any more, the programs carry them:
THIRD-PARTY-LICENSES.txt (written by `cargo xtask licences` from cargo metadata and each shipped
crate's own licence files, 419 crates; `cargo xtask ci` checks it is current) is embedded with
LICENSE-MIT, LICENSE-APACHE and NOTICE in solvecraft_engine::licences, shown in Help ▸ About ▸
Licences (third-party text laid out by visible rows) and printed by `solvecraft-cli licences`.
Scenario s44_about_licences.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

crates/engine/src/lib.rs

@@ -10,6 +10,7 @@
 pub mod cmd;
 pub mod frames;
 pub mod legacy_ids;
+pub mod licences;
 pub mod params;
 pub mod recovery;
 pub mod sample;

crates/engine/src/licences.rs

@@ -0,0 +1,26 @@
+//! SolveCraft's licence texts and the third-party licences, built into every program so a single
+//! downloaded executable carries them (Help ▸ About ▸ Licences, `solvecraft-cli licences`).
+//! THIRD-PARTY-LICENSES.txt is written by `cargo xtask licences` and checked by `cargo xtask ci`.
+
+pub const LICENSE_MIT: &str = include_str!("../../../LICENSE-MIT");
+pub const LICENSE_APACHE: &str = include_str!("../../../LICENSE-APACHE");
+pub const NOTICE: &str = include_str!("../../../NOTICE");
+pub const THIRD_PARTY: &str = include_str!("../../../THIRD-PARTY-LICENSES.txt");
+
+/// Everything, as one text.
+pub fn all() -> String {
+    let rule = "=".repeat(80);
+    format!(
+        "SolveCraft is licensed under the MIT License or the Apache License, Version 2.0, at your option.\n\n{rule}\nNOTICE\n{rule}\n\n{NOTICE}\n{rule}\nLICENSE-MIT\n{rule}\n\n{LICENSE_MIT}\n{rule}\nLICENSE-APACHE\n{rule}\n\n{LICENSE_APACHE}\n{rule}\n{THIRD_PARTY}"
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn the_licences_are_built_in() {
+        assert!(super::LICENSE_MIT.contains("MIT License") && super::LICENSE_APACHE.contains("Apache License"));
+        assert!(super::THIRD_PARTY.contains("truck") && super::THIRD_PARTY.contains("egui"));
+        assert!(super::all().contains("NOTICE"));
+    }
+}