Scaffold cameleer3-server project structure

Multi-module Maven project (server-core + server-app) with Spring Boot 3.4.3,
Gitea CI workflow, and dependency on cameleer3-common from Gitea Maven registry.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -0,0 +1,42 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    container:
+      image: maven:3.9-eclipse-temurin-17
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Configure Gitea Maven Registry
+        run: |
+          mkdir -p ~/.m2
+          cat > ~/.m2/settings.xml << 'SETTINGS'
+          <settings>
+            <servers>
+              <server>
+                <id>gitea</id>
+                <username>claude</username>
+                <password>${env.REGISTRY_TOKEN}</password>
+              </server>
+            </servers>
+          </settings>
+          SETTINGS
+        env:
+          REGISTRY_TOKEN: ${{ secrets.REGISTRY_TOKEN }}
+
+      - name: Cache Maven dependencies
+        uses: actions/cache@v4
+        with:
+          path: ~/.m2/repository
+          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
+          restore-keys: ${{ runner.os }}-maven-
+
+      - name: Build and Test
+        run: mvn clean verify --batch-mode