Quarto extension errors calling pandoc citeproc with file in iCloud storage or with ~ in directory name

Bug description

When using the quarto extension in source mode in a directory with tilde characters embedded in the path name (i.e. a directory on the path has tildes in the name like Foo/tilde~in~name/bug/ ) autocomplete for bibliography fails and spews errors into the Output pane, because the file path is mangled on call to pandoc.

stderr: 'pandoc: /Users/yourname/Foo/tildeinname/bug/minibib.bib: withBinaryFile: does not exist (No such file or directory)\n'

Somehow the ~ is getting stripped from the path before you send a modified version of the file to pandoc. It wouldn't matter except that iCloud storage uses the convention

~/Library/iCloud~md~obsidian/

and I use Obsidian to sync dir with both .md and .qmd files in it.

Note that quarto render works fine

Steps to reproduce

Create a directory tree like this Foo/tilde~in~name/bug

Note that there's a directory in there with a tilde embedded in the name. In the bug directory create test.qmd with this content

---
bibliography: minibib.bib
---

Create the file minibib.bib with valid BibLaTex content like this

@book{durkheim1995,
  title = {The {{Elementary Forms}} of {{Religious Life}}},
  author = {Durkheim, Emile},
  date = {1995-06-01},
  origdate = {1912},
}

In test.qmd type

[@d

Actual behavior

Got error in output

pandoc: /Users/name/Foo/tildeinname/bug/minibib.bib: withBinaryFile: does not exist (No such file or directory)

    at genericNodeError (node:internal/errors:983:15)
    at wrappedFn (node:internal/errors:537:14)
    at checkExecSyncError (node:child_process:930:11)
    at Object.execFileSync (node:child_process:966:15)
    at Object.func (node:electron/js2c/node_init:2:2617)
    at M8 (/Users/name/.positron/extensions/quarto.quarto-1.130.0-universal/out/lsp/lsp.js:122:14901)
    at Object.runPandoc (/Users/name/.positron/extensions/quarto.quarto-1.130.0-universal/out/lsp/lsp.js:122:43358)
    at sqe (/Users/name/.positron/extensions/quarto.quarto-1.130.0-universal/out/lsp/lsp.js:348:16)
    at oqe (/Users/name/.positron/extensions/quarto.quarto-1.130.0-universal/out/lsp/lsp.js:347:1258)
    at B3e.i.bibliographies.length.i.bibliographies.reduce.cslRefs (/Users/name/.positron/extensions/quarto.quarto-1.130.0-universal/out/lsp/lsp.js:347:688) {
  status: 1,
  signal: null,
  output: [
    null,
    '',
    'pandoc: /Users/name/Foo/tildeinname/bug/minibib.bib: withBinaryFile: does not exist (No such file or directory)\n'
  ],
  pid: 3276,
  stdout: '',
  stderr: 'pandoc: /Users/name/Foo/tildeinname/bug/minibib.bib: withBinaryFile: does not exist (No such file or directory)\n'
}

Expected behavior

Autocomplete the reference name and no error

Your environment

Version: Positron 2026.02.1+5 (693b6d13ba5d61566bec7f5a4a46126eff7bbbe1, 2026-02-10T19:05:16.756Z)
Code - OSS version: VS Code 1.106.0
OS version: Darwin arm64 25.2.0
Modes:

System Info

Item	Value
CPUs	Apple M1 Pro (10 x 2400)
GPU Status	2d_canvas: enabled direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: enabled_on trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	9, 6, 6
Memory (System)	32.00GB (1.04GB free)
Process Argv
Screen Reader	no
VM	0%

Extensions (17)

Extension	Author (truncated)	Version
ruff	cha	2026.36.0
vscode-pull-request-github	Git	0.120.2
todo-tree	Gru	0.0.215
vscode-edit-csv	jan	0.11.8
pyrefly	met	0.53.0
debugpy	ms-	2025.18.0
vscode-python-envs	ms-	1.16.0
jupyter	ms-	2025.9.1
jupyter-keymap	ms-	1.1.2
vscode-jupyter-cell-tags	ms-	0.1.9
vscode-jupyter-slideshow	ms-	0.1.6
air-vscode	Pos	0.20.0
publisher	pos	1.31.8
shiny	Pos	1.3.3
quarto	qua	1.130.0
code-spell-checker	str	4.5.6
open-in-external-app	YuT	0.11.2

Start with the Quarto extension's source-mode bibliography autocomplete path that invokes pandoc, using the lsp.js stack trace and the provided reproduction as entry points. Reproduce with a directory containing embedded tildes and test.qmd plus minibib.bib. Done means citation autocomplete succeeds without an Output-pane error while quarto render continues to work.