feat(#106): integrate BlockState machine into PersistMemoryManager

[konard]

Summary

Fixes #106: Integration of BlockState Machine and full migration to its use in PersistMemoryManager.

What changed

• allocator_policy.h (v0.3): Complete rewrite using BlockState machine transitions from block_state.h instead of direct field assignments to BlockHeader:

  • allocate_from_block(): FreeBlock → remove_from_avl → FreeBlockRemovedAVL → [split] SplittingBlock/finalize_split or mark_as_allocated → AllocatedBlock
  • coalesce(): FreeBlockNotInAVL → begin_coalescing → CoalescingBlock → coalesce_with_next/prev → finalize_coalesce → FreeBlock
  • rebuild_free_tree(): calls recover_block_state<A>() per block (Issue интеграция BlockState Machine и полный переход на её использование в PersistMemoryManager #106 requirement)
  • recompute_counters() / repair_linked_list(): use Block<A> field names (weight instead of size)
  • Signature changed: allocate_from_block(base, hdr, uint32_t blk_idx, user_size) and coalesce(base, hdr, uint32_t blk_idx) now accept granule index instead of BlockHeader*

• free_block_tree.h (v1.1): Rewrite AvlFreeTree to use Block<AddressTraitsT>* (BlockT) instead of BlockHeader*, updating all AVL field accesses to Block<A> byte positions (next_offset at byte 4, left_offset at byte 8, etc.)

• types.h (v2.1): Added Block<A>* utilities:

  • block_at_block(), block_idx(Block<A>*), block_total_granules(Block<A>*)
  • is_valid_block(): uses weight (byte 24) instead of size (byte 0)
  • header_from_ptr(): returns Block<A>*, checks weight == 0
  • user_ptr(Block<A>*) overload

• abstract_pmm.h (v0.4): Updated to new API:

  • allocate(): passes idx (uint32_t) to allocate_from_block instead of BlockHeader*
  • deallocate(): uses AllocatedBlock::mark_as_free() state transition
  • init_layout(), do_expand(): use Block<A> fields throughout (no more BlockHeader* direct access)

• tests/test_issue106_block_state_integration.cpp (new): 10 integration test suites verifying state machine transitions in full PMM lifecycle (weight field, allocate/deallocate transitions, coalescing, recover_block_state, detect_block_state, split path)

• docs/atomic_writes.md: Updated to reflect Block<A> layout (weight field), BlockState machine API in state transition diagrams

Binary layout change

The internal block format changed from BlockHeader (size at byte 0) to Block<A> (weight at byte 24). Both are 32 bytes. This is not backward-compatible with existing PMM images created with older versions.

Acceptance criteria

• ✅ No direct assignments to size and root_offset fields in allocator_policy.h (uses state machine methods)
• ✅ All 28 existing tests pass
• ✅ New integration tests added: test_issue106_block_state_integration (10 test suites)

Test plan

• Build with no warnings
• 28 original tests pass
• 1 new test (test_issue106_block_state_integration) passes with 10 test suites:
  • I106-A: Block layout (weight field)
  • I106-B: allocate() state machine transitions
  • I106-C: deallocate() uses AllocatedBlock::mark_as_free()
  • I106-D: coalesce() state machine transitions (right + bidirectional)
  • I106-E: recover_block_state() on load()
  • I106-F: detect_block_state() identifies states correctly
  • I106-G: Full lifecycle with state verification
  • I106-H: Split path creates valid FreeBlock remainder
  • I106-I: Issue интеграция BlockState Machine и полный переход на её использование в PersistMemoryManager #106 acceptance criteria met
  • I106-J: Various block sizes maintain state machine invariants

🤖 Generated with Claude Code

[konard]

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