Pass reserver_ids to SQLite to pre-filter the queried chunks

[ReinierMaas]

This uses the fact that SQLite query engine lives in the same process as the calling Rust code to pass the integers directly into the query via SQL-FFI.

This can be extended to the metastate as well so we don't need to serialize to JSON in order to use the data in the query itself.

[Copilot]

Pull request overview

This PR introduces a SQLite user-defined function (UDF) to let SQLite pre-filter out already-reserved chunks during chunk selection, leveraging in-process FFI to consult the Rust Reserver state while the query executes.

Changes:

• Add opsqueue_is_reserved(submission_id, chunk_index) filtering to all Strategy chunk-selection queries and register the UDF on SQLite connections before fetching.
• Expose Reserver::is_reserved and implement the SQLite UDF callback + destructor wiring (including tests verifying reserved chunks are excluded).
• Minor supporting fixes: lookup_id_by_prefix parameter cleanup and ChunkIndex: TryFrom<i64> for converting SQLite integers safely.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
opsqueue/src/consumer/strategy.rs	Adds opsqueue_is_reserved(...) = 0 filters to strategy queries; updates query-plan tests with a no-op UDF registration.
opsqueue/src/consumer/dispatcher/reserver.rs	Adds Reserver::is_reserved used by the SQLite UDF callback.
opsqueue/src/consumer/dispatcher/mod.rs	Registers the SQLite UDF per acquired reader connection; implements the FFI callback/destructor; adds an integration-style test asserting reserved chunks are excluded.
opsqueue/src/common/submission.rs	Simplifies lookup_id_by_prefix to reuse $1 and avoids redundant bindings.
opsqueue/src/common/chunk.rs	Adds TryFrom<i64> for ChunkIndex to support parsing SQLite int64 values in the UDF.
opsqueue/Cargo.toml	Adds optional libsqlite3-sys dependency gated behind server-logic.
Cargo.lock	Records the new libsqlite3-sys dependency resolution.

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