starknet_committer: collect siblings when traversing the tree

[nimrod-starkware]

Note

Low Risk
Behavior is unchanged for existing callers (they pass None); the new logic only activates when a siblings_map is provided, with the main risk being extra memory/IO retention if misused.

Overview
Extends create_original_skeleton_tree/fetch_nodes traversal to optionally collect DB entries for unmodified sibling subtrees while fetching roots from storage.

This threads a new optional siblings_map: Option<&mut DbHashMap> through get_roots_from_storage and callers; when provided, get_roots_from_storage records the (DbKey, DbValue) for any subtree marked is_unmodified(). All existing call sites (including facts DB traversal and tests) are updated to pass None, preserving current behavior by default.

^{Written by Cursor Bugbot for commit 01a8289. This will update automatically on new commits. Configure here.}

[reviewable-StarkWare]

This change is 

[nimrod-starkware]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• apollo_committer_config: validate config #12728
• starknet_committer_and_os_cli: build storage tries concurrently based on py config #12444
• starknet_patricia_storage: always cache writes in cached storage #12443
• starknet_committer: flush siblings into storage #12272
• starknet_committer: collect storage tries siblings #12271
• starknet_committer: collect siblings when traversing the tree #12270 👈 (View in Graphite)
• starknet_patricia_storage: extend the storage trait to optionally flush to cache #12269
• starknet_patricia_storage: flush explictly to cache #12267 : 1 other dependent PR (#12268 )
• starknet_committer: create storage tries based on config #12441
• starknet_committer: add a field indicating if storage tries should be created concurrently #12440
• starknet_committer: remove code dup for single trie #12201
• starknet_patricia_storage: remove code dup for mget #12175
• starknet_patricia_storage: spawn a task or not based on config #12174
• starknet_patricia_storage: add config field to rocksDB storage #12173
• starknet_patricia_storage: add config field to rocksDB #12172
• starknet_patricia_storage: spawn blocking tasks for rocksDB reads #12168 : 1 other dependent PR (#12169 )
• starknet_committer: parallel reads using unordered futures #12167
• starknet_committer: create sotrage tries sequentially #12166
• starknet_patricia,starknet_committer: dont pass storage mut when not needed #12165
• starknet_patricia_storage: non mut get in storage trait #12123 : 1 other dependent PR (#12252 )
• starknet_patricia_storage: dont cache reads in cached storage #12251
• starknet_patricia_storage: atomic counters for read stats #12122
• main-v0.14.2

This stack of pull requests is managed by Graphite. Learn more about stacking.