ProofWidgets GraphDisplay Not working

* Current lean.nvim version: branch main / commit b2a473c
* Current nvim version: v0.12.2
* Terminal: Ghostty / commit : https://github.com/ghostty-org/ghostty/commits/332b2aefc

Tested on iterm2 as well. I am not able to view any widget. Sample code tested on:

```lean
module

public meta import ProofWidgets.Component.GraphDisplay
public meta import ProofWidgets.Component.HtmlDisplay
public meta import ProofWidgets.Component.InteractiveSvg

public meta section

/-! ## Directed graphs with `GraphDisplay` -/

open ProofWidgets Jsx

/-! ### Basic usage -/

def mkEdge (st : String × String) : GraphDisplay.Edge := {source := st.1, target := st.2}

-- Place your cursor here.
#html
```
Output:
```json
{
defaultEdgeAttrs = { { "fill", "var(--vscode-editor-foreground)" }, { "stroke", "var(--vscode-editor-foreground)" }, { "strokeWidth", 2 }, { "markerEnd", "url(#arrow)" } },
edges = { {
attrs = {},
source = "b",
target = "c"
}, {
attrs = {},
source = "d",
target = "e"
}, {
attrs = {},
source = "e",
target = "f"
}, {
attrs = {},
source = "f",
target = "d"
} },
forces = { {
link = vim.empty_dict()
}, {
manyBody = vim.empty_dict()
}, {
x = vim.empty_dict()
}, {
y = vim.empty_dict()
} },
showDetails = false,
vertices = { {
boundingShape = {
circle = {
radius = 5
}
},
id = "a",
label = {
element = { "circle", { { "r", 5 }, { "fill", "var(--vscode-editor-background)" }, { "stroke", "var(--vscode-editor-foreground)" }, { "strokeWidth", 1.5 } }, {} }
}
}, {
boundingShape = {
circle = {
radius = 5
}
},
id = "b",
label = {
element = { "circle", { { "r", 5 }, { "fill", "var(--vscode-editor-background)" }, { "stroke", "var(--vscode-editor-foreground)" }, { "strokeWidth", 1.5 } }, {} }
}
}, {
boundingShape = {
circle = {
radius = 5
}
},
id = "c",
label = {
element = { "circle", { { "r", 5 }, { "fill", "var(--vscode-editor-background)" }, { "stroke", "var(--vscode-editor-foreground)" }, { "strokeWidth", 1.5 } }, {} }
}
}, {
boundingShape = {
circle = {
radius = 5
}
},
id = "d",
label = {
element = { "circle", { { "r", 5 }, { "fill", "var(--vscode-editor-background)" }, { "stroke", "var(--vscode-editor-foreground)" }, { "strokeWidth", 1.5 } }, {} }
}
}, {
boundingShape = {
circle = {
radius = 5
}
},
id = "e",
label = {
element = { "circle", { { "r", 5 }, { "fill", "var(--vscode-editor-background)" }, { "stroke", "var(--vscode-editor-foreground)" }, { "strokeWidth", 1.5 } }, {} }
}
}, {
boundingShape = {
circle = {
radius = 5
}
},
id = "f",
label = {
element = { "circle", { { "r", 5 }, { "fill", "var(--vscode-editor-background)" }, { "stroke", "var(--vscode-editor-foreground)" }, { "strokeWidth", 1.5 } }, {} }
}
} }
}
```

I tried toggling on the enable widget and checkhealth didn't indicate anything. Also installed resvg but also nothing. Above snippet works on `vscode`

Reproduce the supplied Lean snippet using ProofWidgets.Component.GraphDisplay in lean.nvim, with widgets enabled, and compare the result with VS Code. Start by tracing how lean.nvim handles the GraphDisplay widget output; done means the graph is visible in Neovim and the behavior is verified without relying on resvg.

Written by the indexing model from the issue text.