feat: add Bun and Deno test jobs to CI

[jhnns]

Summary

• Adds parallel test-bun and test-deno jobs to the test-and-release workflow, running the unit test suite under each runtime to verify cross-runtime compatibility.
• Adds .tool-versions pinning Bun 1.3.14 and Deno 2.9.0, read by both the GH Actions setup steps and by mise locally.
• Dependencies are installed via npm ci in each job; Bun runs tests with bun --bun to force its own runtime (overriding the #!/usr/bin/env node shebang), and coverage is disabled in the Bun job since V8 coverage APIs are unavailable there.
• The new jobs run in parallel with test-and-release but do not currently gate the release step.

🤖 Generated with Claude Code

[coveralls]

Coverage Report for CI Build 30771988306

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No base build found for commit f1a4ba0 on main.
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Coverage: 85.714%

Details

• Patch coverage: No coverable lines changed in this PR.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

Requires a base build to compare against. How to fix this →

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Coverage Stats

Relevant Lines:	7
Covered Lines:	5
Line Coverage:	71.43%
Relevant Branches:	7
Covered Branches:	7
Branch Coverage:	100.0%
Branches in Coverage %:	Yes
Coverage Strength:	3.57 hits per line

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💛 - Coveralls