chore: add Renovate configuration and workflows

- Introduced .renovaterc for Renovate settings.
- Added renovate.config.cjs for Gitea integration.
- Created .gitea/workflows/renovate.yml for daily Renovate runs.
- Added .gitea/workflows/test.yml for CI testing.
- Removed outdated GitHub workflows and configuration files.

.github/renovate.json

@@ -1,16 +0,0 @@
-{
-  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
-  "extends": ["config:recommended", ":disableDependencyDashboard"],
-  "assignees": ["valentineus"],
-  "labels": ["dependencies", "automated"],
-  "packageRules": [
-    {
-      "description": "Group patch & minor updates together",
-      "groupName": "all digest updates",
-      "groupSlug": "all-digest",
-      "matchUpdateTypes": ["minor", "patch", "pin", "digest"],
-      "matchPackageNames": ["*"],
-      "automerge": true
-    }
-  ]
-}

.github/workflows/ci.yml

@@ -1,28 +0,0 @@
-name: CI
-
-on:
-  push:
-    branches: [master]
-  pull_request:
-    branches: [master]
-
-permissions:
-  contents: read
-
-jobs:
-  test:
-    name: Test
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v5
-      - name: Set up Node.js
-        uses: actions/setup-node@v5
-        with:
-          node-version: 22
-      - name: Install dependencies
-        run: npm ci
-      - name: Run checks
-        run: npm run check
-      - name: Run type checks
-        run: npm run typecheck

.github/workflows/mirror.yml

@@ -1,25 +0,0 @@
-name: Mirror
-
-on:
-  push:
-    branches: [master]
-  pull_request:
-    branches: [master]
-
-permissions:
-  contents: read
-
-jobs:
-  mirror:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v5
-        with:
-          fetch-depth: 0
-      - name: Mirror to remote repository
-        uses: yesolutions/mirror-action@master
-        with:
-          REMOTE: "https://git.popov.link/popov.link.git"
-          GIT_USERNAME: ${{ secrets.GIT_USERNAME }}
-          GIT_PASSWORD: ${{ secrets.GIT_PASSWORD }}