split: CI workflows, scripts, root tooling, and docs

Forgejo workflows (new), GitHub workflow tweaks, .gitignore/.vscode, root
package-lock, rustfmt.toml, scripts/* updates, docs/ updates including
data-flow / authentication / server-setup, CLAUDE.md and README updates.

.forgejo/workflows/deploy-docs.yml

@@ -0,0 +1,38 @@
+name: Deploy Documentation
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - "docs/**"
+      - ".forgejo/workflows/deploy-docs.yml"
+  workflow_dispatch:
+
+concurrency:
+  group: pages
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Setup Node.js environment
+        uses: actions/setup-node@v4
+        with:
+          node-version: "25.x"
+
+      - name: Build docs
+        run: scripts/build-docs.sh
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: docs
+          path: docs/.vitepress/dist