[kvlonge]

Why

Rust-hosted SQLBuild port: Phase 3 (CHI-592) moves the sqb compile command's output and artifact handling into Rust; Phase 1 (CHI-589) continues with discovery.

Changes

• sqb compile text and JSON reports, semantic-check notice and diagnostics rendering moved to sqlbuild-core (cli_text).
• target/ writing (compiled/run SQL, manifest, SQL test artifacts and their cache), artifact staging and atomic publish (PreparedCompileArtifacts), and compile-reuse recording are native; the compile driver calls them directly.
• Deleted cli/commands/_helpers/compile/, prepared_compile_artifacts.py, native_artifact_batch.py and the full-compile recording pieces of cli/compile_reuse/.
• Discovery: the D016 project Python path check and model header value parsing are native.
• Four Python entry modules called only from Rust get a leading _.
• Movable Python: 120,834 → 118,042 lines.

Intentional differences: the artifact-write recorder is passed explicitly per compile instead of a global registry; the header parse cache clears when full instead of evicting LRU; header syntax errors no longer chain their cause.

Verification

• Old vs new on 372 project copies (cold, reuse hit, manifest/DAG, forced colour, lineage modes, select/exclude, edits): no differences.
• Compiler differential: 371 projects as expected; byte-identical compile output on a 1k-model project and a large private project.
• 8,499 focused tests including compile-reuse and rule-gate e2e; make check-ci; hygiene scan.
• Independent review: no findings.