IGNITE-28418 Add more diagnostic to page lock timeouts

[ibessonov]

https://issues.apache.org/jira/browse/IGNITE-28418

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[Copilot]

Pull request overview

This PR (IGNITE-28418) enhances diagnostics for page/off-heap lock acquisition timeouts by capturing and reporting additional context about the lock holder.

Changes:

• Extend OffheapReadWriteLock off-heap state to store the current write-lock owner thread id and include it in timeout diagnostics.
• Update PageHeader in-memory header layout to account for the larger lock structure and make flag updates CAS-based.
• Add ThreadUtils.dumpThread(...) helper to dump a single thread by id; minor refactor in synchronizer dump handling.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
modules/page-memory/src/main/java/org/apache/ignite/internal/pagememory/persistence/PageHeader.java	Recomputes header offsets/overhead using the new lock size; makes flag updates atomic (CAS).
modules/core/src/main/java/org/apache/ignite/internal/util/OffheapReadWriteLock.java	Adds write-owner thread id tracking in offheap memory and emits thread dump + ownerId on lock timeout.
modules/core/src/main/java/org/apache/ignite/internal/thread/ThreadUtils.java	Adds single-thread dump utility and tightens null-handling for locked synchronizers output.

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