Codebasis als Dateien ins Arbeitsrepo statt als Gitlink

QuellCode/CentronERP war nur als Gitlink (Submodul-Referenz auf 79c1142)
getrackt, ohne .gitmodules und ohne erreichbares Remote. Der
Untersuchungsgegenstand der Versuchsreihe war damit nicht reproduzierbar
gesichert: Ein Klon haette ein leeres Verzeichnis erhalten, und die Belege
der 3.287 Anforderungen waeren nicht ueberpruefbar gewesen.

Umstellung:
- Historie nach c:\DEV\CentronERP_git_snapshot_79c1142 ausgelagert
  (vollstaendig lesbar, enthaelt 79c1142 und Vorgaenger 89ccfd6)
- Gitlink aus dem Index entfernt
- Dateiinhalt aufgenommen: 24.557 Dateien, rund 333 MB

Die verschachtelte .gitignore der Codebasis gilt weiter, Build-Artefakte
bleiben ausgeschlossen. Details in Versuche/Versuch_01/_Codebasis-Nachweis.md

QuellCode/CentronERP/.github/workflows/cleanup-pr-artifacts.yml

@@ -0,0 +1,117 @@
+name: Clean up closed PR artifacts
+
+on:
+  pull_request_target:
+    types:
+      - closed
+
+permissions:
+  actions: write
+  pull-requests: read
+
+jobs:
+  delete-artifacts:
+    name: Delete PR artifacts
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+      - name: Delete artifacts from PR workflow runs
+        uses: actions/github-script@v9
+        with:
+          script: |
+            const { owner, repo } = context.repo;
+            const pullRequest = context.payload.pull_request;
+
+            const workflowRuns = await github.paginate(
+              github.rest.actions.listWorkflowRunsForRepo,
+              {
+                owner,
+                repo,
+                event: 'pull_request',
+                branch: pullRequest.head.ref,
+                per_page: 100
+              }
+            );
+
+            const pullRequestRuns = [];
+            const associatedPullRequestsBySha = new Map();
+
+            for (const run of workflowRuns) {
+              if (!associatedPullRequestsBySha.has(run.head_sha)) {
+                const associatedPullRequests = await github.paginate(
+                  github.rest.repos.listPullRequestsAssociatedWithCommit,
+                  {
+                    owner,
+                    repo,
+                    commit_sha: run.head_sha,
+                    per_page: 100
+                  }
+                );
+
+                associatedPullRequestsBySha.set(run.head_sha, associatedPullRequests);
+              }
+
+              const belongsToPullRequest = associatedPullRequestsBySha
+                .get(run.head_sha)
+                .some(pr => pr.number === pullRequest.number);
+
+              if (belongsToPullRequest) {
+                pullRequestRuns.push(run);
+              }
+            }
+
+            let deletedArtifacts = 0;
+            let deletedBytes = 0;
+
+            for (const run of pullRequestRuns) {
+              const artifacts = await github.paginate(
+                github.rest.actions.listWorkflowRunArtifacts,
+                {
+                  owner,
+                  repo,
+                  run_id: run.id,
+                  per_page: 100
+                }
+              );
+
+              for (const artifact of artifacts) {
+                if (artifact.expired) {
+                  core.info(`Skipping expired artifact ${artifact.name} (${artifact.id}).`);
+                  continue;
+                }
+
+                try {
+                  await github.rest.actions.deleteArtifact({
+                    owner,
+                    repo,
+                    artifact_id: artifact.id
+                  });
+
+                  deletedArtifacts += 1;
+                  deletedBytes += artifact.size_in_bytes;
+                  core.info(`Deleted artifact ${artifact.name} (${artifact.id}).`);
+                } catch (error) {
+                  if (error.status === 404) {
+                    core.info(`Artifact ${artifact.name} (${artifact.id}) was already deleted.`);
+                    continue;
+                  }
+
+                  throw error;
+                }
+              }
+            }
+
+            const deletedMiB = (deletedBytes / 1024 / 1024).toFixed(1);
+            core.info(
+              `Deleted ${deletedArtifacts} artifact(s) (${deletedMiB} MiB) ` +
+              `from ${pullRequestRuns.length} workflow run(s) for PR #${pullRequest.number}.`
+            );
+
+            await core.summary
+              .addHeading('PR artifact cleanup')
+              .addRaw(`Pull request: #${pullRequest.number}`, true)
+              .addRaw(`Workflow runs inspected: ${pullRequestRuns.length}`, true)
+              .addRaw(`Artifacts deleted: ${deletedArtifacts}`, true)
+              .addRaw(`Storage released: ${deletedMiB} MiB`, true)
+              .write();