fix(sqlite-vfs): use delete range for truncate cleanup

[NathanFlurry]

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[NathanFlurry]

• chore(engine): publish engine bases in ci #4649 : 3 dependent PRs (#4650 , #4652 , #4666 )
• chore: lockfile lefthook #4647
• fix(rivetkit): surface native sqlite kv errors to callers #4645
• fix(rivetkit): prevent sleep races during disconnect and db work #4644
• fix(rivetkit): isolate engine envoys and propagate startup failures #4643
• test(rivetkit): remove wasm sqlite-only fixtures and coverage #4642
• chore(sqlite-vfs): remove wasm sqlite packages and workspace wiring #4641
• chore(rivetkit): remove wasm sqlite runtime #4614
• fix(sqlite-native): restore native startup kv preload #4639
• fix(sqlite-native): delete metadata before chunk range #4638
• fix(sqlite-native): keep truncate cache coherent #4637
• fix(sqlite-vfs): use delete range for truncate cleanup #4636 👈 (View in Graphite)
• fix(sqlite-native): restore kv error hook #4635
• perf(sqlite-native): avoid cloning cached read chunks #4634
• perf(sqlite-native): gate kv operation labels #4633
• perf(sqlite-native): reuse read cache for partial writes #4632
• perf(sqlite-native): remove delete file existence probe #4631
• fix(sqlite-native): gate native read cache behind env var #4630
• fix(pegboard): isolate runner config dc lookup failures #4625 : 1 other dependent PR (#4626 )
• docs(pegboard): note runner config upsert split write risk #4624
• fix(pegboard): unpack global runner config keys correctly #4623
• fix(pegboard-gateway): enforce tunnel message state #4622
• fix(pegboard-runner): clear terminal tunnel routes #4621
• fix(pegboard): skip protocol version keys in runner pool backfill #4620
• fix(pegboard): create missing normal runner configs #4619
• fix(epoxy): reuse cached optimistic value #4618
• main

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

[claude]

Review: fix(sqlite-vfs): use delete range for truncate cleanup

The changes look correct and consistent. Both the Rust and TypeScript VFS truncate implementations are now in sync, matching the CLAUDE.md parity requirement.

What this does

The truncate path previously iterated chunk indices from lastChunkToKeep + 1 to lastExistingChunk, batching individual deleteBatch/kv_delete calls in groups of up to KV_MAX_BATCH_KEYS. The PR replaces this with a single deleteRange call from lastChunkToKeep + 1 to getChunkKeyRangeEnd(fileTag).

Correctness

Parity with CLAUDE.md requirements: the spec explicitly says both implementations must use deleteRange for the truncate strategy. This PR brings both into compliance.

Edge case size == 0: when truncating to zero, last_chunk_to_keep = -1 (Rust) / lastChunkToKeep = -1 (TypeScript). The start key becomes getChunkKey(fileTag, 0), correctly deleting all chunks. The (last_chunk_to_keep + 1) as u32 Rust cast is safe because -1i64 + 1 = 0i64, which casts cleanly to 0u32.

Strictly more thorough: the old code deleted chunks only in [lastChunkToKeep+1, lastExistingChunk]. The new range end getChunkKeyRangeEnd(fileTag) covers all chunks for the file tag including any orphaned chunks beyond lastExistingChunk. This matches how delete_file already works.

Atomic: the old batch-delete loop was not atomic across batches when the chunk count exceeded KV_MAX_BATCH_KEYS. A single deleteRange is atomic.

KV_MAX_BATCH_KEYS not orphaned: the constant is still used on the write path (lines 933/935 in vfs.rs) so removing it from the truncate path does not leave dead code.

Minor observations

• No tests were added. The existing suite likely covers truncate behavior indirectly, but an explicit test for the size == 0 and size > 0 && size % CHUNK_SIZE == 0 truncate paths on both VFS implementations would add confidence.
• The PR description template was left blank. Describing the behavioral difference (range vs. batch enumerate) and the CLAUDE.md compliance angle would help with future archaeology.
• docs-internal/engine/NATIVE_SQLITE_DATA_CHANNEL.md referenced in CLAUDE.md does not exist in the repo yet. When it is added, the truncate-via-deleteRange strategy should be documented there.

Summary

The change is correct, efficient, and brings both VFS implementations in line with documented requirements. Approving with the minor note about test coverage.