fix: exit with code 1 when GitHub download fails in add command

Also add CHANGELOG note about stricter build canister name validation.

Made-with: Cursor

Author: Kamirus

cli/CHANGELOG.md

@@ -12,6 +12,7 @@
 - Fix corrupted `mops.lock` file causing an unhandled crash instead of a helpful error message
 - Fix `mops sources` resolving package config from wrong directory in some contexts
 - Harden lock file integrity check against package ID prefix collisions
+- `mops build` now reports invalid canister names instead of silently ignoring them
 - Document `baseDir`, `readme`, and `dfx` fields in `[package]` config
 
 ## 2.4.0

cli/commands/add.ts

@@ -105,7 +105,7 @@ export async function add(
       verbose: verbose,
     });
     if (!res) {
-      return;
+      process.exit(1);
     }
   } else if (!pkgDetails.path) {
     let res = await installMopsDep(pkgDetails.name, pkgDetails.version, {