Support core dump on snapshots created from snapshot/disk

[ludfjig]

Closes #1617 by fixing symbol resolution for sandboxes created from snapshots. The binary path is left empty, but this is on purpose, I don't think there's any advantage of plumbing through and saving the file name.

Note that no snapshot version bump is needed, this is a backwards compatible change (old snapshots continue to load and work fine)

please review commit by commit.

[Copilot]

Pull request overview

This PR aims to make guest core dumps usable for sandboxes restored from on-disk snapshots by preserving the original ELF entry point across the Initialise -> Call transition and across snapshot save/restore, so AT_ENTRY can be populated correctly for PIE symbol resolution in debuggers (per #1617).

Changes:

• Rename the snapshot/VM “entrypoint” state to next_action and thread it through snapshot restore and VM setup paths.
• Persist a new original_entrypoint/original_entrypoint_addr field (with backward-compatible deserialization) so core-dump code can emit a correct AT_ENTRY.
• Add a GDB-based regression test ensuring symbol resolution works for crash dumps produced from snapshot-created sandboxes.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/hyperlight_host/src/sandbox/uninitialized_evolve.rs	Use mgr.original_entrypoint to seed runtime crashdump config; pass mgr.next_action into VM creation.
src/hyperlight_host/src/sandbox/snapshot/mod.rs	Rename entrypoint to next_action; add/persist original_entrypoint and accessors.
src/hyperlight_host/src/sandbox/snapshot/file/mod.rs	Include original_entrypoint in on-disk config and restore it when loading snapshots.
src/hyperlight_host/src/sandbox/snapshot/file/config.rs	Add original_entrypoint_addr with #[serde(default)] for backward-compatible snapshot config reads.
src/hyperlight_host/src/sandbox/initialized_multi_use.rs	Update restore/snapshot paths to use next_action and VM get/set_next_action.
src/hyperlight_host/src/mem/mgr.rs	Track next_action plus original_entrypoint in the memory manager and propagate into snapshots/restores.
src/hyperlight_host/src/hypervisor/hyperlight_vm/x86_64.rs	Rename VM field to next_action; use runtime-config entry point for crashdump AT_ENTRY behavior.
src/hyperlight_host/src/hypervisor/hyperlight_vm/mod.rs	Rename VM field and accessor methods to next_action.
src/hyperlight_host/src/hypervisor/hyperlight_vm/aarch64.rs	Rename VM field to next_action and update initialization/dispatch logic accordingly.
src/hyperlight_host/examples/crashdump/main.rs	Add a new GDB-based test validating symbol resolution for crash dumps generated from snapshot-created sandboxes.