Chore/sibujs quality followups

[hexplus]

Description

Restores the test coverage that the duplicate-instance hardening shims reduced — pure test/coverage work, no behavior change.

The globalThis first-copy-wins registries added for duplicate-runtime resilience have a "a duplicate copy loaded" branch that the normal suite can't reach (the source module evaluates exactly once, always taking the first-copy path), which left track.ts at 33% branch and batch.ts at 90%.

• Adds tests/duplicate-instance-source.test.ts — covers the duplicate-detection path on the real source modules by pre-seeding the globalThis registry as if a first copy had published its API, then freshly importing the module so its resolver executes the duplicate branch (delegates to the first copy, dev-warns once, batch re-exports the first copy's functions).
• Adds a justified /* v8 ignore */ on the __SIBU_VERSION__ build-define branch in track.ts (only inlined by the bundler, never reachable in source tests — matches the existing __SIBU_DEV__ pattern in dev.ts).

Result: track.ts and batch.ts are back to 100% across all metrics. Full suite: 321 files / 3954 tests pass.

Related Issue

Closes #

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

(Test coverage / chore — none of the above categories apply; no production behavior change.)

Checklist

• I have read CONTRIBUTING.md
• My code builds without errors
• I have tested my changes
• I have updated documentation if needed