fix: enforce LF line endings to prevent CRLF diff churn (#299)

## Fix: Enforce LF line endings repo-wide

### Problem
Windows-based agents produce CRLF line endings, causing git diffs to
show every line as changed (1000+ line "rewrites" that are actually
20-line patches). This has hit us on `manage.sh`, `deploy.yml`, and
multiple PRs.

### Fix
Added `* text=auto eol=lf` to `.gitattributes`. Git will now:
- Store all text files as LF in the repo
- Convert CRLF to LF on commit (regardless of OS)
- Check out as LF on all platforms

Also marks common binary formats explicitly.

### Impact
Existing files with CRLF will be normalized on their next commit. No
functional changes.

Co-authored-by: Kpa-clawbot <259247574+Kpa-clawbot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.gitattributes

@@ -1,3 +1,12 @@
+# Force LF line endings for all text files (prevents CRLF churn from Windows agents)
+* text=auto eol=lf
+
+# Explicitly mark binary files
+*.png binary
+*.jpg binary
+*.ico binary
+*.db binary
+
 # Squad: union merge for append-only team state files
 .squad/decisions.md merge=union
 .squad/agents/*/history.md merge=union