chore: define repository line endings

[thomhurst]

Summary

• Normalize tracked text files to LF through .gitattributes.
• Preserve CRLF for future Windows batch files and LF for shell scripts.
• Run git add --renormalize .; tracked blobs were already normalized, so the PR contains no noisy whole-repository rewrite.

Why

Repository-level attributes make checkouts deterministic across platforms and prevent core.autocrlf warnings from obscuring real changes.

Test plan

• dotnet test TomLonghurst.EnumerableAsyncProcessor.sln -c Release (1,074 passed across net8.0 and net9.0)
• git diff --cached --check
• git check-attr text eol -- README.md scripts/AgentLocks.ps1 .gitattributes
• Commit completed without line-ending warnings

Closes #342

[greptile-apps]

Greptile Summary

This PR defines consistent repository line endings through .gitattributes. The main changes are:

• Normalize automatically detected text files to LF.
• Preserve CRLF for Windows batch and command scripts.
• Require LF for shell scripts.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
.gitattributes	Adds repository-wide text normalization with platform-appropriate overrides for batch and shell scripts.

_{Reviews (1): Last reviewed commit: "chore: define repository line endings" | Re-trigger Greptile}