test: add local dstack e2e stack

[kvinwang]

Summary

• add e2e/run.sh to launch a local full dstack stack: KMS, gateway, VMM, and configurable app CVMs
• document e2e usage, status/log/smoke/cleanup commands, and the no-QEMU KMS validation mode
• generate compact unified measurement.json during image build and include it in image digests/tarballs
• bump the dstack submodule to feat: add TDX qemu-free verification mode dstack#742 for vm_config-selected TDX measurement verification without adding a new attestation wire variant
• make --kms-no-qemu skip KMS image cache pre-population so the new verifier path cannot rely on a downloaded image
• allow no-QEMU measurement mode at exactly 2048 MiB or at least 2816 MiB; other low-memory sizes are rejected because QEMU's patched kernel Authenticode hash is memory-dependent there
• update e2e image-cache alias extraction to read compact measurement.json hashes (tdx.h / snp.h, with old os_image_hash fallback)

Depends on: Dstack-TEE/dstack#742

Validation

• bash -n mkimage.sh e2e/run.sh && shellcheck e2e/run.sh
• rebuilt guest image with ../build.sh guest
  • confirmed build/images/dstack-0.6.0/measurement.json is compact schema v2: top-level v/tdx/snp, subdocument v/h/m
  • confirmed each h equals sha256(hex_decode(m))
  • confirmed no plaintext/hash-field names in the hashed payload JSON: no base_cmdline, kernel_sha384, rootfs_hash, kernel_cmdline_sha384, kernel_cmdline_sha256, initrd_size, measurement, os_image_hash, or version
  • current file size: 1196 bytes; TDX CBOR payload: 268 bytes; SNP CBOR payload: 234 bytes
• local full-stack no-QEMU KMS e2e passed at default 2048 MiB with:
  • E2E_APP_TIMEOUT=900 ./e2e/run.sh up --image dstack-0.6.0 --apps 1 --force --kms-image-verify --kms-no-qemu
  • confirmed KMS PATH=/usr/sbin:/usr/bin:/sbin:/bin and no dstack-acpi-tables in PATH
  • confirmed no KMS image cache pre-population / no image download log in measurement mode
  • confirmed tdx_attestation_variant = "measurement", embedded tdx_measurement uses only v/h/m, and app memory is 2147483648 bytes
  • confirmed GetAppKey success
• local legacy KMS image-verification e2e also passed without --kms-no-qemu
  • confirmed KMS image cache pre-populates 3 aliases (digest.txt, TDX h, SNP h)
  • confirmed legacy vm_config omits tdx_attestation_variant / tdx_measurement and keeps the digest.txt os_image_hash path

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.