feat: Further limit message memory on small nodes

[schneiderstefan]

This PR addresses an issue when running a subnet with nodes that have limited RAM. The message memory, i.e. the storage required by messages in queues, used to be bound only by a constant of 20 GB. This is however not safe as they are currently kept fully in RAM, and some newer nano nodes will have as little as 8 GB of RAM.

Those subnets however already limit the heap delta using a parameter in the registry, as the heap delta is also stored in RAM. This commit simply reuses the heap delta limit to also give an upper bound on the message memory. Both bounded and unbounded wait messages are now limited to min(heap_delta/3, old_constant). On large nodes, this commit makes no difference at all.

Most code changes are due to the fact that message memory is no longer a fixed value that can be set at replica startup, and accompanying necessary changes to the test framework.

[github-actions]

This pull request changes code owned by the Governance team. Therefore, make sure that
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1. Update unreleased_changelog.md (if there are behavior changes, even if they are
   non-breaking).

2. Are there BREAKING changes?

3. Is a data migration needed?

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[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to 2af38e7.

Security Overview

• 🔎 Scanned files: 14 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/f5e9d2bb-29a4-4b64-902a-391d65fd8b2d?scanId=128b8f61-c9f4-4c2f-93ca-c423c44c326b&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
Enhancement	► rs/config/src/execution_environment.rs     Convert SUBNET_HEAP_DELTA_CAPACITY from crate-private to public; add helper functions for message memory capacities and heap delta capacity calculations; add heap_delta_capacity_for_message_memory helper; implement message_memory_capacity logic; expose capacity fields in Config and tests updates to use new helpers and state metadata
Enhancement	► rs/execution_environment/src/execution_environment.rs     Use guaranteed_response_message_memory_capacity via state.metadata instead of config field; rely on heap delta capacity and new functions to determine capacity
Enhancement	► rs/execution_environment/src/scheduler/test_utilities.rs     Update test builder and defaults to use maximum_state_delta (heap delta capacity) rather than direct guaranteed/best-effort memory fields; propagate maximum_state_delta into test state setup
Enhancement	► rs/messaging/BUILD.bazel     Add dependency on registry/resource_limits in test suite
Enhancement	► rs/messaging/src/message_routing.rs     Adjust StreamHandlerImpl creation to remove direct hypervisor_config usage; rely on metadata-based capacities
Enhancement	► rs/messaging/src/routing/stream_handler.rs     Remove direct guaranteed_response_message_memory_capacity field from StreamHandlerImpl; stop passing hypervisor_config; use metadata-based capacity
Enhancement	► rs/messaging/src/routing/stream_handler/tests.rs     Refactor tests to supply memory limits via heap_delta_capacity_for_message_memory and maximum_state_delta; adapt test setup helpers accordingly
Enhancement	► rs/messaging/src/state_machine.rs     Shed messages using capacity from state.metadata.best_effort_message_memory_capacity() instead of a fixed field; align with new metadata-based capacity
Enhancement	► rs/messaging/src/state_machine/tests.rs     Update tests to accommodate removal of direct hypervisor_config fields; rely on metadata-based capacities and test scaffolding changes
Enhancement	► rs/messaging/tests/common/mod.rs     Update test subnet config to use ResourceLimits for maximum_state_delta via heap_delta_capacity_for_message_memory; simplify hypervisor config initialization
Enhancement	► rs/registry/resource_limits/src/lib.rs     Add maximum_state_delta_or(default) helper to choose registry override or default heap delta capacity
Enhancement	► rs/replicated_state/src/metadata_state.rs     Expose guaranteed_response_message_memory_capacity and best_effort_message_memory_capacity methods; add heap_delta_capacity helper and compute capacities from heap delta capacity; use maximum_state_delta_or for effective capacity
Enhancement	► rs/state_machine_tests/src/lib.rs Introduce resource_limits field in StateMachineConfig; add with_resource_limits builder; propagate resource_limits into StateMachine initialization
Enhancement	► rs/state_machine_tests/src/lib.rs Thread resource_limits into multi-subnet setup and state creation for tests
Enhancement	► rs/test_utilities/execution_environment/src/lib.rs Use heap_delta_capacity_for_message_memory to configure maximum_state_delta for tests; propagate resource limits into execution test builder setup

[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to 2af38e7.

Security Overview

• 🔎 Scanned files: 14 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/f975f1a5-0a47-4a3b-b7f0-a55609e90390?scanId=acb855d8-6cea-4a7f-b16c-5b2bfbdadd6a&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
Enhancement	► rs/config/src/execution_environment.rs     Convert SUBNET_HEAP_DELTA_CAPACITY from crate-private to public; add helper functions for message memory capacities and heap delta capacity calculations; add heap_delta_capacity_for_message_memory helper; implement message_memory_capacity logic; expose capacity fields in Config and tests updates to use new helpers and state metadata
Enhancement	► rs/execution_environment/src/execution_environment.rs     Use guaranteed_response_message_memory_capacity via state.metadata instead of config field; rely on heap delta capacity and new functions to determine capacity
Enhancement	► rs/execution_environment/src/scheduler/test_utilities.rs     Update test builder and defaults to use maximum_state_delta (heap delta capacity) rather than direct guaranteed/best-effort memory fields; propagate maximum_state_delta into test state setup
Enhancement	► rs/messaging/BUILD.bazel     Add dependency on registry/resource_limits in test suite
Enhancement	► rs/messaging/src/message_routing.rs     Adjust StreamHandlerImpl creation to remove direct hypervisor_config usage; rely on metadata-based capacities
Enhancement	► rs/messaging/src/routing/stream_handler.rs     Remove direct guaranteed_response_message_memory_capacity field from StreamHandlerImpl; stop passing hypervisor_config; use metadata-based capacity
Enhancement	► rs/messaging/src/routing/stream_handler/tests.rs     Refactor tests to supply memory limits via heap_delta_capacity_for_message_memory and maximum_state_delta; adapt test setup helpers accordingly
Enhancement	► rs/messaging/src/state_machine.rs     Shed messages using capacity from state.metadata.best_effort_message_memory_capacity() instead of a fixed field; align with new metadata-based capacity
Enhancement	► rs/messaging/src/state_machine/tests.rs     Update tests to accommodate removal of direct hypervisor_config fields; rely on metadata-based capacities and test scaffolding changes
Enhancement	► rs/messaging/tests/common/mod.rs     Update test subnet config to use ResourceLimits for maximum_state_delta via heap_delta_capacity_for_message_memory; simplify hypervisor config initialization
Enhancement	► rs/registry/resource_limits/src/lib.rs     Add maximum_state_delta_or(default) helper to choose registry override or default heap delta capacity
Enhancement	► rs/replicated_state/src/metadata_state.rs     Expose guaranteed_response_message_memory_capacity and best_effort_message_memory_capacity methods; add heap_delta_capacity helper and compute capacities from heap delta capacity; use maximum_state_delta_or for effective capacity
Enhancement	► rs/state_machine_tests/src/lib.rs Introduce resource_limits field in StateMachineConfig; add with_resource_limits builder; propagate resource_limits into StateMachine initialization
Enhancement	► rs/state_machine_tests/src/lib.rs Thread resource_limits into multi-subnet setup and state creation for tests
Enhancement	► rs/test_utilities/execution_environment/src/lib.rs Use heap_delta_capacity_for_message_memory to configure maximum_state_delta for tests; propagate resource limits into execution test builder setup

[daniel-wong-dfinity-org-twin]

Approving tiny change in Governance-owned code.