[Bug] Error upon modifying role rank using drag-and-drop

[magic-spearmint]

Description

Dragging and dropping a server role to change its ranking results in the following error message:

Unexpected token '<', "<!DOCTYPE "... is not valid JSON

The role's position within the list will appear to have been modified, but navigating away from the role management page and then returning to it reveals that no modification was actually committed.

Host Information

Operating system(s)

• Microsoft Windows 10 Pro 19045.6388 (22H2, x86_64)
• Manjaro Linux (stable branch, amd64, KDE 25.08-1/Plasma 6.3.6-1)

Browser(s)

• Vivaldi 7.6.3797.58
• Waterfox 6.6.3

Additional Details

Developer Console Log (Vivaldi)

13:39:18.857 index-DHlqcFl0.js:2 ⮿ PATCH https://stoat.chat/api/servers/01K4NQHX4N250SDVAY51S6WZJB/roles/ranks? 500 (Internal Server Error)
             req              @ index-DHlqcFl0.js:2
             patch            @ index-DHlqcFl0.js:2
             setRoleOrdering  @ index-DHlqcFl0.js:7
             mutationFn       @ index-DHlqcFl0.js:322
             fn               @ index-DHlqcFl0.js:2
             g                @ index-DHlqcFl0.js:2
             start            @ index-DHlqcFl0.js:2
             execute          @ index-DHlqcFl0.js:2
             await in execute
             mutate           @ index-DHlqcFl0.js:2
             i                @ index-DHlqcFl0.js:2
             s                @ index-DHlqcFl0.js:10
             ig               @ index-DHlqcFl0.js:10
             i                @ index-DHlqcFl0.js:10
             setTimeout
             une              @ index-DHlqcFl0.js:10
             og               @ index-DHlqcFl0.js:10
13:39:18.857 index-DHlqcFl0.js:334 🛈 components/modal — modal renderer created for type: error2
13:39:18.859 index-DHlqcFl0.js:2 🛈 Fetch failed loading: PATCH {PH3}.
             req              @ index-DHlqcFl0.js:2
             patch            @ index-DHlqcFl0.js:2
             setRoleOrdering  @ index-DHlqcFl0.js:7
             mutationFn       @ index-DHlqcFl0.js:322
             fn               @ index-DHlqcFl0.js:2
             g                @ index-DHlqcFl0.js:2
             start            @ index-DHlqcFl0.js:2
             execute          @ index-DHlqcFl0.js:2
             await in execute
             mutate           @ index-DHlqcFl0.js:2
             i                @ index-DHlqcFl0.js:2
             s                @ index-DHlqcFl0.js:10
             ig               @ index-DHlqcFl0.js:10
             i                @ index-DHlqcFl0.js:10
             setTimeout
             une              @ index-DHlqcFl0.js:10
             og               @ index-DHlqcFl0.js:10

Screenshot