CARS-29365: fix documentation

[martin-dessureault]

What

This PR performs a Documentation Accuracy Audit for the req_fuse repository as part of the Marketplace Documentation & Governance initiative. It updates outdated references, fixes typos, adds missing documentation, and brings the change log up to date with the current version.

Changes include:

• Updated version references in README from 0.2 to 0.3 (current version is 0.3.2)
• Fixed broken image reference (removed non-existent assets/logo.png object tag)
• Added Telemetry section to README documenting the [:req_fuse, :blown] event
• Updated CHANGELOG.md with missing entries for versions 0.3.0 and 0.3.2
• Fixed typo in mix.exs description (ttps:// → https://)

Why

Documentation audit to ensure all references, commands, and descriptions are accurate and current. This improves:

• Developer onboarding experience
• LLM tool accuracy (e.g., Cursor) when referencing this codebase
• Overall documentation trustworthiness

Jira ticket

CARS-29365

Steps to Validate/Verify

1. Review the README for accurate version numbers and working image
2. Verify the new Telemetry section matches the implementation in lib/telemetry.ex
3. Confirm CHANGELOG entries align with git history

Additional Notes

• No breaking changes
• No code changes to library functionality
• The telemetry documentation already existed in lib/telemetry.ex module docs; this PR surfaces it in the README for better discoverability

After merge checklist:

• Update version in mix.exs if releasing a new version
• Update CHANGELOG.md with changes
• Create and push a new git tag if releasing: git tag -a X.Y.Z -m "vX.Y.Z" && git push origin X.Y.Z
• Check GitHub Actions to make sure CI passes