Initial: MPQ patch packager (Gitea Action, StormLib-based)

A BigWigs-style CI packager for WoW MPQ patch archives. Reads an mpq.yaml
manifest, stages files, builds a vanilla-1.12-compatible patch-X.mpq via
StormLib, and (in the example workflow) attaches it to a Gitea release on tag.

action.yml

@@ -0,0 +1,35 @@
+name: "MPQ Packager"
+description: "Pack a WoW interface repo into a vanilla-compatible patch-X.mpq using StormLib."
+author: "paste"
+
+inputs:
+  manifest:
+    description: "Path to the MPQ manifest, relative to the repo root."
+    required: false
+    default: "mpq.yaml"
+  version:
+    description: "Release version stamped into @project-version@ (defaults to the tag/ref name)."
+    required: false
+    default: ""
+  out-dir:
+    description: "Directory the built .mpq is written to."
+    required: false
+    default: "dist"
+
+outputs:
+  mpq-path:
+    description: "Filesystem path of the built .mpq."
+  mpq-name:
+    description: "Filename of the built .mpq (e.g. patch-Z.mpq)."
+
+runs:
+  using: "docker"
+  image: "Dockerfile"
+  env:
+    INPUT_MANIFEST: ${{ inputs.manifest }}
+    INPUT_VERSION: ${{ inputs.version }}
+    INPUT_OUT_DIR: ${{ inputs.out-dir }}
+
+branding:
+  icon: "package"
+  color: "purple"