Use LfmbTree for locks, introducing LockIndex and an index from LockId

[limemloh]

Purpose

Implements the real persistent state model for protocol-level locks, replacing the dummy in-memory BTreeMap-backed implementation. Closes COR-2295.

Changes

• Introduced LockIndex: a sequential internal key type for the lock LfmbTree, consistent with how TokenIndex works for tokens. It is intentionally internal and must never appear in the public API, events, or state hashing.

• Replaced BTreeMap<LockId, PersistentLockP11> with LfmbTree<LockIndex, Option<PersistentLockP11>>: the tree uses None entries as tombstones for deleted (cancelled) locks. A companion im::HashMap<LockId, LockIndex> serves as a derived in-memory
  reverse index, rebuilt on every load from the blob store by scanning the tree and reading each live lock's configuration.

• Embedded LockId inside LockConfiguration: the create_lock call no longer takes a separate lock_id argument — the ID is extracted from the configuration. This avoids dual-passing and makes the configuration self-contained.

• Changed delete_lock to return bool: the return type changed from Option<LockP11> (the deleted lock) to bool (whether a lock was deleted). All callers already held a LockP11 reference and only needed to know whether deletion occurred.

• PersistentLockP11::configuration stored as HashedCacheableRef: the lock configuration is now stored as a blob-store reference rather than inlined, consistent with how token configuration is stored.

• Fixed lock_list ordering and documented the lack of guarantee: the switch from BTreeMap to im::HashMap for the internal index means lock_list no longer returns lock IDs in sorted order. The trait doc now explicitly states no ordering guarantee and
  warns callers not to drive state-mutating scheduler operations from the unordered iterator without first sorting, to preserve consensus safety.

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG.

CLA acceptance

_Remove if not applicable.

By submitting the contribution I accept the terms and conditions of the
Contributor License Agreement v1.0

• link: https://developers.concordium.com/CLAs/Contributor-License-Agreement-v1.0.pdf

• I accept the above linked CLA.

[codecov]

Codecov Report

❌ Patch coverage is 89.43396% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.14%. Comparing base (404cb8f) to head (4addeb1).
⚠️ Report is 3 commits behind head on release/p11.

Files with missing lines	Patch %	Lines
...block-state/src/entity/protocol_level_locks/p11.rs	82.45%	10 Missing ⚠️
plt/plt-block-state/src/block_state.rs	28.57%	5 Missing ⚠️
plt/plt-block-state/src/persistent/cacheable.rs	0.00%	5 Missing ⚠️
plt/plt-block-state/src/persistent/blob_store.rs	84.21%	3 Missing ⚠️
...k-state/src/persistent/protocol_level_locks/p11.rs	94.73%	3 Missing ⚠️
plt/plt-block-state/src/persistent/hash.rs	80.00%	1 Missing ⚠️
plt/plt-scheduler/src/scheduler/plt_scheduler.rs	96.29%	1 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           release/p11    #1652      +/-   ##
===============================================
+ Coverage        64.07%   64.14%   +0.06%     
===============================================
  Files              376      376              
  Lines            75007    75150     +143     
  Branches          3013     3014       +1     
===============================================
+ Hits             48064    48208     +144     
+ Misses           23930    23928       -2     
- Partials          3013     3014       +1     

Files with missing lines	Coverage Δ
...cordiumTests/EndToEnd/CredentialDeploymentTests.hs	82.26% <100.00%> (ø)
...mTests/EndToEnd/TransactionTableIntegrationTest.hs	91.50% <100.00%> (ø)
...s/consensus/ConcordiumTests/KonsensusV1/CatchUp.hs	82.15% <100.00%> (ø)
...us/ConcordiumTests/KonsensusV1/Consensus/Blocks.hs	76.02% <100.00%> (ø)
plt/plt-block-state/src/entity/block_state/p11.rs	98.30% <100.00%> (ø)
.../plt-block-state/src/persistent/block_state/p11.rs	97.64% <100.00%> (+0.30%)	⬆️
plt/plt-scheduler/src/locks/lock_configuration.rs	92.95% <100.00%> (ø)
plt/plt-block-state/src/persistent/hash.rs	94.73% <80.00%> (-5.27%)	⬇️
plt/plt-scheduler/src/scheduler/plt_scheduler.rs	79.86% <96.29%> (+0.31%)	⬆️
plt/plt-block-state/src/persistent/blob_store.rs	78.78% <84.21%> (+7.53%)	⬆️
... and 4 more

... and 6 files with indirect coverage changes