feat: update item version on put

[jason-lynch]

Summary

Adds a new feature to storage.Put operations to optionally update the value version after the put succeeds. This mechanism works whether the operation is executed by itself or within a transaction. The version is used as a constraint in update operations, so this feature enables us to hold a reference to a value and perform multiple update operations on it without needing to get the value from Etcd in between.

We had some unused mock operations in the storagetest package, and I opted to remove them in this commit rather than update them for this change.

Testing

This feature is used by the next PR in this sequence. In this PR, it's only used in the unit/narrow integration tests, so there are no functional changes.

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📝 Walkthrough

Walkthrough

This PR introduces version updating capabilities to put operations in the storage layer. A new VersionUpdater interface enables operations to request post-write version updates based on previous etcd key-value data. Implementations across put, create, and update operations support this functionality, with transaction execution applying updates during commit.

Changes

Cohort / File(s)	Summary
Version Updater Interface server/internal/storage/interface.go	Introduced VersionUpdater interface with UpdateVersionEnabled() and UpdateVersion(prevKVs) methods. Added WithUpdatedVersion() method to PutOp[V Value] and embedded VersionUpdater interface.
Put Operation Implementation server/internal/storage/put.go	Implemented version updating across putOp, createOp, and updateOp with shouldUpdateVersion flag and helper functions extractPrevKVs() and updateVersion(). Updated Exec to capture previous key-value data from etcd responses and apply version updates. Adjusted putOps to avoid mutating caller-provided options slice.
Transaction Version Updates server/internal/storage/txn.go	Enhanced txn.Commit() to extract previous key-value data and invoke UpdateVersion() on operations that have version updating enabled.
Version Update Tests server/internal/storage/put_test.go, server/internal/storage/txn_test.go	Added subtests validating version increment behavior in put/create/update operations and transactions with WithUpdatedVersion(). Tests verify version transitions and multi-operation transaction semantics.
Removed Test Helpers server/internal/storage/storagetest/ops.go	Removed entire test helper file containing seven fake operation constructors and implementations for storage operations.

Poem

🐰 Hop hop, the versions dance with glee,
From etcd's store, they're wild and free!
Each put and create now track the past,
With versions updated, forever to last,
Our whiskers twitch at this feature so keen,
The finest version updates we've seen! 🥕

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 27.27% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'feat: update item version on put' clearly and concisely summarizes the main feature addition in the changeset.
Description check	✅ Passed	The description covers Summary, Changes, and Testing sections and explains the feature purpose and scope, but is missing Checklist items and Issue link.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/put-with-updated-version

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[jason-lynch]

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Actionable comments posted: 1

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Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@server/internal/storage/interface.go`:
- Around line 137-139: Fix the minor typo in the UpdateVersion method comment:
replace "upate" with "update" in the comment that currently reads "and upate its
item's versions" so the sentence correctly reads "and update its item's
versions"; the comment is adjacent to the UpdateVersion(prevKVs
map[string]*mvccpb.KeyValue) declaration referencing prevKVs and
mvccpb.KeyValue.

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ℹ️ Review info

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Configuration used: Organization UI

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Run ID: 266eee22-9a52-4e02-abf1-30b153218a23

📥 Commits

Reviewing files that changed from the base of the PR and between 0eba7c4 and fa785be.

📒 Files selected for processing (6)

• server/internal/storage/interface.go
• server/internal/storage/put.go
• server/internal/storage/put_test.go
• server/internal/storage/storagetest/ops.go
• server/internal/storage/txn.go
• server/internal/storage/txn_test.go

💤 Files with no reviewable changes (1)

• server/internal/storage/storagetest/ops.go