refactor: rename Send-PveIso to Send-PveFile and move VM provisioning into integration tests

Send-PveFile replaces Send-PveIso with a -ContentType parameter
(iso, vztmpl, import). This is a breaking rename — the module has
not been released yet.

Test infrastructure refactored:
- prepare-test-vm.sh replaced with prepare-test-environment.sh
  (only SSH ops: enable content types, upload cloud-init snippet,
  curl download cloud image)
- VM provisioning moved into integration tests as "Linux VM —
  Provisioning" context: Send-PveFile, New-PveVm, Import-PveVmDisk,
  Set-PveVmConfig, Set-PveCloudInitConfig, Start-PveVm,
  Test-PveVmGuestAgent — all tested as part of the test suite
- PVETEST_LINUX_VMID env var removed (VM created by tests)
- PVETEST_CLOUD_IMAGE_PATH + PVETEST_PASSWORD added

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

.github/workflows/integration-tests.yml

@@ -275,19 +275,17 @@ jobs:
 
       # ── Prepare test Linux VM ────────────────────────────────────────
 
-      - name: Deploy test Linux VM to nested PVE
+      - name: Prepare test environment on nested PVE
         if: inputs.skip_provision != true
-        id: linux_vm
+        id: test_env
         shell: bash
         run: |
-          OUTPUT=$(bash ${SCRIPTS_DIR}/prepare-test-vm.sh \
+          OUTPUT=$(bash ${SCRIPTS_DIR}/prepare-test-environment.sh \
             "${{ steps.provision.outputs.host }}" \
             "${PVE_PASSWORD}" \
-            200 \
-            "${{ steps.target.outputs.node }}" \
-            "${{ steps.provision.outputs.token }}")
-          LINUX_VMID=$(echo "$OUTPUT" | grep "^LINUX_VMID=" | cut -d= -f2)
-          echo "linux_vmid=${LINUX_VMID}" >> "$GITHUB_OUTPUT"
+            "${RUNNER_TEMP}")
+          CLOUD_IMAGE_PATH=$(echo "$OUTPUT" | grep "^CLOUD_IMAGE_PATH=" | cut -d= -f2)
+          echo "cloud_image_path=${CLOUD_IMAGE_PATH}" >> "$GITHUB_OUTPUT"
 
       # ── Run tests ─────────────────────────────────────────────────────
 
@@ -304,7 +302,8 @@ jobs:
           PVETEST_NODE: ${{ steps.target.outputs.node }}
           PVETEST_STORAGE: ${{ steps.target.outputs.storage }}
           PVETEST_PVE_VERSION: ${{ matrix.pve_version }}
-          PVETEST_LINUX_VMID: ${{ steps.linux_vm.outputs.linux_vmid }}
+          PVETEST_PASSWORD: ${{ env.PVE_PASSWORD }}
+          PVETEST_CLOUD_IMAGE_PATH: ${{ steps.test_env.outputs.cloud_image_path }}
         run: |
           $env:PVETEST_ISO_PATH = Join-Path $env:RUNNER_TEMP "pvetest.iso"
           Import-Module Pester -MinimumVersion 5.0