Implement dynamic storage for storage declaration and std

[ironcev]

Description

This PR is a part of #7560 implementation and implements:

• storage fields access compilation for dynamic storage.
• dynamic storage for all the types and functions in the std::storage module, except the StorageVec.

In the storage_api, support for dynamic storage is added as the extension to the existing API based on quads. The reason is that we will need to support quad-based storage for backwards compatibility, for contracts that cannot migrate all the data, but still want to use, in parallel, the benefits of dynamic storage.

The existing API is marked as deprecated in favor of the new API in which the function suffix, either quads or slot(s), clearly indicates what kind of storage access the function performs.

Additionally, the existing clear API that returned boolean information about slot occupancy is split into two distinctive APIs: clear that only clears and doesn't return occupancy information, and clear_existed that returns boolean information about slot occupancy.

Introducing two variants for clearing is done for performance reasons. Returning the occupancy information in dynamic storage case requires more gas, and in many of the cases that information is not needed. Having two distinctive function allows developers to opt-in for the cost.

Additionally, the PR:

• fixes bug in ir_generation::purity::check_function_purity where StateUpdateSlot IR instruction and supd/supi opcodes were still be considered as reading and writing operations instead of only writing.
• closes Fix issues found during testing of the Iterator implementation for StorageVec #6829 by properly documenting the semantic of zero-sized types in relation to storage.

Planned next steps are:

• Adding additional comprehensive test coverage. Some of the existing tests are adapted to test the new API and dynamic storage in this PR. Considering the impact of the change, unlike for other experimental feature, we want dynamic storage test to be included in all the tests that are currently testing storage.
• Further optimizing writing to storage by supporting __state_store_slot in the StorageKey. __state_store_slot intrinsic is used in storage types, e.g. when storing slices or inserting into a StorageMap, but currently not in the StorageKey in general. There, __state_update_slot is always used. Supporting __state_store_slot in the StorageKey requires introduction of an additional abstraction that will allow us to express that a StorageKey points to a value that is guaranteed to be the only value in the slot.
• Enabling SDK tests for StorageVecs that are temporarily disabled. This will be done when dynamic storage version of StorageVec is implemented.
• Emitting <project>-storage_slots.json for dynamic storage and properly consuming them in the SDK. Until then, some of the tests are disabled and marked as TODO: (INIT-STORAGE).

Checklist

• I have linked to any relevant issues.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation where relevant (API docs, the reference, and the Sway book).
  • If my change requires substantial documentation changes, I have requested support from the DevRel team
• I have added tests that prove my fix is effective or that my feature works.
• I have added (or requested a maintainer to add) the necessary Breaking* or New Feature labels where relevant.
• I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• I have requested a review from the relevant team or maintainers.

[cursor]

PR Summary

High Risk
Touches core storage key generation, IR emission, and standard-library storage primitives, which can affect on-chain data layout/compatibility and correctness across many programs.

Overview
Implements experimental dynamic storage end-to-end: IR generation now builds StorageKey values differently when context.experimental.dynamic_storage is enabled (byte offsets + dynamic slots) and the typed storage access model is updated to carry a full storage_field_path for key derivation.

Extends std::storage with explicit APIs for quad-slot vs dynamic-slot operations (*_quads, *_slot(s), plus update_slot/append_slot) while deprecating the legacy read/write/clear/read_slice/write_slice APIs; updates StorageKey, StorageMap, StorageString, and StorageBytes to use the new primitives (with cfg-split behavior) and clarifies zero-sized “storage type” semantics.

Fixes purity analysis to treat StateUpdateSlot/supd/supi as write-only (not read+write), and updates/expands tests for the new storage intrinsics and CEI/purity expectations.

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[ironcev]

👍

[codspeed-hq]

Merging this PR will not alter performance

✅ 25 untouched benchmarks

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_{Comparing ironcev/dynamic-storage-std-and-storage-declaration (271d72c) with master (e12e611)}

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