ci: Add CI workflows

The push.yml workflow builds the manager and then places it in the $HOME
of the runner.  The issue.ym then uses the cached tool binary to update
the techtree information whenever any issue is changed.  This approach
of course only works as long as only one runner is connected to this
repository.

In the long run, this approach shall be replaced by a nix build of the
techtree-manager which is then cached by the OS instead of manually.

.forgejo/workflows/issue.yml

@@ -0,0 +1,14 @@
+on:
+  issues:
+    types: [opened, reopened, closed, labeled, unlabeled, edited]
+
+jobs:
+  test:
+    runs-on: self-hosted-nixos-x86_64
+    steps:
+      - uses: https://data.forgejo.org/actions/checkout@v4
+      - name: Check techtree-manager presence
+        run: |
+          test -e ~/.cache/fafo-techtree/techtree-manager
+      - name: Run techtree-manager
+        run: cd techtree-manager/ && nix-shell shell.nix --run ~/.cache/fafo-techtree/techtree-manager

.forgejo/workflows/push.yml

@@ -0,0 +1,14 @@
+on:
+  push:
+
+jobs:
+  build:
+    runs-on: self-hosted-nixos-x86_64
+    steps:
+      - uses: https://code.forgejo.org/actions/checkout@v4
+      - name: Build techtree manager tool
+        run: cd techtree-manager/ && nix-shell shell.nix --run "cargo build --release"
+      - name: Cache the techtree manager tool
+        run: |
+          mkdir -p ~/.cache/fafo-techtree
+          cp -v techtree-manager/target/release/techtree-manager ~/.cache/fafo-techtree/techtree-manager