fix: remove stray conflict markers from .gitignore

Leftover <<<<<<</=======/>>>>>>> from an earlier dev merge that got committed
unresolved; keep the real ignore rules (*.db, /data/, /data-dev/, .aider*).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -220,7 +220,6 @@ marimo/_static/
 marimo/_lsp/
 __marimo__/
 
-<<<<<<< HEAD
 # Seismo Fleet Manager
 # SQLite database files
 *.db
@@ -228,6 +227,3 @@ __marimo__/
 /data/
 /data-dev/
 .aider*
-.aider*
-=======
->>>>>>> 0c2186f5d89d948b0357d674c0773a67a67d8027