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.

.github/workflows/e2e.yml

@@ -6,7 +6,7 @@ on:
   pull_request:
     branches: ["main"]
   schedule:
-    - cron: '0 * * * *'
+    - cron: "0 * * * *"
   workflow_dispatch:
 
 concurrency:
@@ -28,13 +28,13 @@ jobs:
       - name: Setup Node.js environment
         uses: actions/setup-node@v4.2.0
         with:
-          node-version: "22.x"
+          node-version: "25.x"
           check-latest: true
 
       - name: Setup Rust toolchain
         uses: dtolnay/rust-toolchain@stable
         with:
-          toolchain: "1.89.0"
+          toolchain: "1.92.0"
           components: clippy, rustfmt
 
       - name: Setup rust