fix: disable gzip to work around deflate panic on x86_64-linux

the stdlib deflate decompressor panics with "reached unreachable code"
on certain gzip responses when running on x86_64-linux. setting
Accept-Encoding: identity avoids triggering the decompressor.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[e-mail]>

src/internal/xrpc.zig

···
         defer aw.deinit();
 
         // build extra headers for auth
-        var extra_headers: std.http.Client.Request.Headers = .{};
+        // disable gzip to work around deflate decompressor panic on x86_64-linux
+        var extra_headers: std.http.Client.Request.Headers = .{
+            .accept_encoding = .{ .override = "identity" },
+        };
         var auth_header_buf: [256]u8 = undefined;
         if (self.access_token) |token| {
             const auth_value = try std.fmt.bufPrint(&auth_header_buf, "Bearer {s}", .{token});
···
     try std.testing.expect(std.mem.startsWith(u8, url, "https://bsky.social/xrpc/app.bsky.actor.getProfile?"));
     try std.testing.expect(std.mem.indexOf(u8, url, "actor=did%3Aplc%3Atest123") != null);
 }
+