build: optimize CI cache usage and add fast lint gate (#3251)

* build: optimize CI cache usage and add fast lint gate

This PR addresses cache storage approaching its 10GB limit by:

1. Cache optimization (saves ~2+ GB):
   - Remove Java version from cargo cache key (Rust target is JDK-independent)
   - Use actions/cache/restore + actions/cache/save pattern
   - Only save cache on main branch, not on PRs

2. Reduce Rust test matrix:
   - Consolidate from 2 jobs (Java 11 + Java 17) to 1 job (Java 17)
   - Rust code is JDK-independent, so no coverage lost

3. Add fast lint gate (~30 seconds):
   - New lint job runs cargo fmt --check before expensive builds
   - build-native and linux-test-rust depend on lint passing
   - Fail fast on formatting errors instead of waiting 5-10 minutes
   - macOS lint runs on ubuntu-latest for cost efficiency

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: add missing datafusion-datasource dependency

The csv_scan.rs file added in #3044 uses datafusion_datasource but
the dependency was not added to core/Cargo.toml.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* build: merge TPC-DS/TPC-H correctness tests into pr_build_linux

These workflows verify that benchmark queries produce correct results
(not actual performance benchmarks), so they can use the CI build profile
and share the native library artifact from build-native.

Changes:
- Add verify-benchmark-results-tpch job to pr_build_linux
- Add verify-benchmark-results-tpcds job to pr_build_linux (3 join strategies)
- Delete standalone benchmark-tpcds.yml and benchmark-tpch.yml workflows
- Jobs reuse native library artifact instead of rebuilding

This eliminates 4+ redundant native builds per PR.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: compile test classes before generating TPC data

The GenTPCHData and GenTPCDSData classes are test classes that need
to be compiled before running exec:java. Added a build step to compile
the project (including test classes) before data generation.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: andygrove

.github/actions/rust-test/action.yaml

@@ -21,11 +21,7 @@ description: "Run Rust tests"
 runs:
   using: "composite"
   steps:
-    - name: Check Cargo fmt
-      shell: bash
-      run: |
-        cd native
-        cargo fmt --all -- --check --color=never
+    # Note: cargo fmt check is now handled by the lint job that gates this workflow
 
     - name: Check Cargo clippy
       shell: bash