fix: V8 coverage innermost-wins across FunctionCoverage entries

[SutuSebastian]

Summary

V8 can emit nested functions as separate FunctionCoverage entries. Innermost-wins was applied per entry, so an outer whole-file range listed after an inner range could mark nested lines as covered incorrectly.

Fix: flatten all ranges for a script, sort globally by descending byte span, then write line hits (smallest range wins).

Test plan

• New test: inner count: 0 entry before outer whole-file count: 2 — inner stays uncovered
• Existing single-entry nesting test unchanged
• bun test src/application/coverage-engine.test.ts
• bun run typecheck
• CI green

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: cf6b75fc-0476-47e8-99cb-7ac384196a8f

📥 Commits

Reviewing files that changed from the base of the PR and between eb18750 and 999d86c.

📒 Files selected for processing (3)

• .changeset/fix-v8-coverage-innermost-wins.md
• src/application/coverage-engine.test.ts
• src/application/coverage-engine.ts

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/v8-coverage-innermost-wins

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[changeset-bot]

🦋 Changeset detected

Latest commit: 999d86c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@stainless-code/codemap	Patch

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