nightly: add workflow_dispatch branch input

Allows manually triggering the nightly build against any branch from
the GitHub Actions UI or gh CLI, without editing the workflow file.
Scheduled runs are unaffected (input is empty, falls back to github.ref_name).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: masterpiga

.github/workflows/nightly.yml

@@ -4,6 +4,11 @@ on:
   schedule:
     - cron: "0 0 * * *"
   workflow_dispatch:
+    inputs:
+      branch:
+        description: 'Branch to build (leave empty to use the branch this workflow runs from)'
+        required: false
+        default: ''
 
 permissions:
   contents: read
@@ -18,8 +23,6 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-22.04, ubuntu-24.04-arm]
-        branch:
-          - { code: master, label: gitmaster }
         include:
           - os: ubuntu-22.04
             compiler: { compiler: GNU12, CC: gcc-12, CXX: g++-12, packages: gcc-12 g++-12 }
@@ -34,8 +37,8 @@ jobs:
       CMAKE_BUILD_TYPE: ${{ matrix.btype }}
       GENERATOR: ${{ matrix.generator }}
       TARGET: ${{ matrix.target }}
-      BRANCH: ${{ matrix.branch.code }}
-      BUILD_NAME: ${{ matrix.branch.label }}
+      BRANCH: ${{ inputs.branch || github.ref_name }}
+      BUILD_NAME: ${{ inputs.branch || github.ref_name }}
     steps:
       - name: Install compiler ${{ matrix.compiler.compiler }}
         run: |
@@ -159,7 +162,7 @@ jobs:
         run: |
           # Note that we can't make a shallow clone to reduce clone traffic and time, as we have to
           # fetch the entire history to correctly generate the version for the AppImage filename
-          git clone -b ${{ github.ref_name }} https://github.com/${{ github.repository }} src
+          git clone -b ${{ inputs.branch || github.ref_name }} https://github.com/${{ github.repository }} src
           pushd src
           git submodule init
           git config submodule.src/tests/integration.update none
@@ -293,7 +296,7 @@ jobs:
         run: |
           # Note that we can't make a shallow clone to reduce clone traffic and time, as we have to
           # fetch the entire history to correctly generate the version for the installation package filename
-          git clone -b ${{ github.ref_name }} https://github.com/${{ github.repository }} src
+          git clone -b ${{ inputs.branch || github.ref_name }} https://github.com/${{ github.repository }} src
           pushd src
           git submodule init
           git config submodule.src/tests/integration.update none
@@ -368,7 +371,7 @@ jobs:
         run: |
           # Note that we can't make a shallow clone to reduce clone traffic and time, as we have to
           # fetch the entire history to correctly generate the version for the disk image filename
-          git clone -b ${{ github.ref_name }} https://github.com/${{ github.repository }} src
+          git clone -b ${{ inputs.branch || github.ref_name }} https://github.com/${{ github.repository }} src
           pushd src
           git submodule init
           git config submodule.src/tests/integration.update none