build: replace hash with build increment in slackware txz pkg (#1449)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Introduced support for specifying and propagating a build number
throughout the build process, including command-line options and
workflow inputs.
* TXZ package naming and URLs now include the build number for improved
traceability.

* **Improvements**
* Enhanced robustness in locating TXZ files with improved fallback
logic, especially in CI environments.
* Improved flexibility and validation of environment schema for plugin
builds.

* **Style**
  * Minor formatting corrections for consistency and readability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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plugin/package.json

@@ -12,7 +12,7 @@
     "tsx": "^4.19.2",
     "zod": "^3.24.1",
     "zx": "^8.3.2"
-},
+  },
   "type": "module",
   "license": "GPL-2.0-or-later",
   "scripts": {