Normalize line endings to LF via .gitattributes

Adds a committed .gitattributes so Windows and Linux checkouts converge
on LF for all text files, overriding each developer's local core.autocrlf.
Renormalizes existing blobs (server.py, dashboard.html, etc.) that had
CRLF baked in, clearing the repo-wide phantom "modified" churn.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitattributes

@@ -0,0 +1,28 @@
+# Normalize line endings across Windows/Linux checkouts.
+# All text files are stored as LF in the repo and checked out as LF
+# on every OS. Git auto-detects text vs binary.
+* text=auto eol=lf
+
+# Explicitly binary — never touch these bytes.
+*.png binary
+*.jpg binary
+*.jpeg binary
+*.gif binary
+*.ico binary
+*.pdf binary
+*.zip binary
+*.gz binary
+*.tar binary
+*.wasm binary
+*.sqlite binary
+*.sqlite3 binary
+*.safetensors binary
+*.gguf binary
+
+# Scripts that must stay LF even if someone forces CRLF locally.
+*.sh text eol=lf
+*.py text eol=lf
+
+# Windows batch files genuinely need CRLF.
+*.bat text eol=crlf
+*.cmd text eol=crlf