feat: Implement LLM provider deletion and refactor ConfigManager to preserve unknown payload sections.

.gitattributes

@@ -0,0 +1,21 @@
+* text=auto eol=lf
+
+*.bat text eol=crlf
+*.cmd text eol=crlf
+*.ps1 text eol=crlf
+
+*.png binary
+*.jpg binary
+*.jpeg binary
+*.gif binary
+*.ico binary
+*.pdf binary
+*.zip binary
+*.gz binary
+*.tar binary
+*.db binary
+*.sqlite binary
+*.p12 binary
+*.pfx binary
+*.crt binary
+*.pem binary