Overhaul VirtFusion provider: 20 resources, 30 data sources, multipage pagination

Complete rewrite of the VirtFusion Terraform provider with full API coverage:

- 20 managed resources (server, build, SSH key, user, firewall, IP blocks, etc.)
- 30 data sources (hypervisors, packages, servers, IP blocks, self-service, etc.)
- New HTTP client with proper error handling, query parameter support, and
  automatic multipage pagination via GetAllPages (fetches all pages from
  Laravel-style paginated endpoints and merges into a single response)
- Fixed type mismatches against live API: ServerData.Suspended (int→bool),
  IPBlockData.Type (string→int), PackageData json tags (primaryStorage, etc.),
  ServerData nested CPU/Settings/Resources structure, HypervisorGroupResources
  array response
- Configurable results-per-page (default 300) on all list data sources
- Migrated CI from GitHub Actions to Gitea Actions
- Updated goreleaser config, go.mod dependencies, and examples

Verified against live VirtFusion instance at cp.vps.ezscale.tech:
all data sources return correct data with full pagination support.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/ci.yaml

@@ -0,0 +1,33 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Build
+        run: go build -v ./...
+
+      - name: Lint
+        uses: golangci/golangci-lint-action@v6
+        with:
+          version: latest
+
+      - name: Test
+        run: go test -race -v ./internal/...
+
+      - name: Check go generate
+        run: |
+          go generate ./...
+          git diff --exit-code || (echo "go generate produced changes; please run 'go generate ./...' and commit" && exit 1)