[Bug] Custom themes diff overrides not applying

Bug Description
Custom themes diff overrides not working

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.1.132
• Feedback ID: 7e5b95f9-9a2a-4902-b02f-3155045e3ab3

<img width="446" height="325" alt="Image" src="https://github.com/user-attachments/assets/f5faddfc-2907-4be4-86d7-9694326081d8" />

<img width="937" height="487" alt="Image" src="https://github.com/user-attachments/assets/1b40990a-f671-4965-b5e3-892df7fc582a" />

When I create a custom theme with these values, it's not picking up all of my overrides.

{
    "name": "Rosé Pine",
    "base": "dark",
    "overrides": {
        "claude": "rgb(196,167,231)",
        "claudeShimmer": "rgb(235,188,186)",

        "text": "rgb(224,222,244)",
        "inverseText": "rgb(25,23,36)",
        "inactive": "rgb(110,106,134)",
        "inactiveShimmer": "rgb(144,140,170)",
        "subtle": "rgb(64,61,82)",
        "suggestion": "rgb(156,207,216)",
        "permission": "rgb(196,167,231)",
        "permissionShimmer": "rgb(235,188,186)",
        "remember": "rgb(235,188,186)",

        "success": "rgb(156,207,216)",
        "error": "rgb(235,111,146)",
        "warning": "rgb(246,193,119)",
        "warningShimmer": "rgb(250,215,160)",
        "merged": "rgb(196,167,231)",

        "promptBorder": "rgb(82,79,103)",
        "promptBorderShimmer": "rgb(144,140,170)",
        "planMode": "rgb(156,207,216)",
        "autoAccept": "rgb(49,116,143)",
        "bashBorder": "rgb(246,193,119)",
        "ide": "rgb(196,167,231)",
        "fastMode": "rgb(235,111,146)",
        "fastModeShimmer": "rgb(235,188,186)",

        "diffAdded": "rgb(40,82,96)",
        "diffRemoved": "rgb(102,42,70)",
        "diffAddedDimmed": "rgb(30,56,66)",
        "diffRemovedDimmed": "rgb(68,34,52)",
        "diffAddedWord": "rgb(64,128,152)",
        "diffRemovedWord": "rgb(235,111,146)",

        "userMessageBackground": "rgb(31,29,46)",
        "userMessageBackgroundHover": "rgb(38,35,58)",
        "messageActionsBackground": "rgb(64,61,82)",
        "bashMessageBackgroundColor": "rgb(38,35,58)",
        "memoryBackgroundColor": "rgb(38,35,58)",
        "selectionBg": "rgb(64,61,82)",

        "rate_limit_fill": "rgb(196,167,231)",
        "rate_limit_empty": "rgb(33,32,46)",
        "briefLabelYou": "rgb(156,207,216)",
        "briefLabelClaude": "rgb(196,167,231)",

        "red_FOR_SUBAGENTS_ONLY": "rgb(235,111,146)",
        "blue_FOR_SUBAGENTS_ONLY": "rgb(156,207,216)",
        "green_FOR_SUBAGENTS_ONLY": "rgb(49,116,143)",
        "yellow_FOR_SUBAGENTS_ONLY": "rgb(246,193,119)",
        "purple_FOR_SUBAGENTS_ONLY": "rgb(196,167,231)",
        "orange_FOR_SUBAGENTS_ONLY": "rgb(235,188,186)",
        "pink_FOR_SUBAGENTS_ONLY": "rgb(235,188,186)",
        "cyan_FOR_SUBAGENTS_ONLY": "rgb(156,207,216)"
    }
}