Project specify port for localhost

Bug description

When I render a Quarto qmd file "--to clean-revealjs" or "--to html" in VSCode via the preview button or CTRL-SHIFT-K Quarto uses a random port for the localhost. The Quarto Project Options and the Quarto Creating a Website states one can insert:

project:    
  preview: 
    port: 4200

However, despite having inserted this option into the project's _quarto.yml a random port number is still used. Other options in the _quarto.yml file are being applied, so I know the manifest is found and read. Some others have reported the same experience:

https://stackoverflow.com/questions/75715950/quarto-project-specify-port-for-localhost

Also tried setting the browser option to true and false which also had no effect.

project:    
  preview: 
    port: 4200
    browser: true

When the preview is re-rendered automatically after a change, then having a different port number is disruptive to the development workflow experience when showing the preview in both the VSCode preview and a browser.

Steps to reproduce

1. Add to the project directory a _quarto.yml file that contains:

project:    
  preview: 
    port: 4200

2. Open a .qmd file in VSCode with the Quarto extension.

3. Preview the .qmd document with CTRL-SHIFT-P | Quarto Preview Format... | format: clean-revealjs or format: html

Observe the quarto command in the terminal is missing the --port option.

No matter the port number specified, Quarto continues to choose a random port number instead of accepting the project.preview.port value in _quarto.yml.

Expected behavior

Terminal output for the preview command should say:

quarto preview [...qmd file...] --no-browser --no-watch-inputs --port 4200

Actual behavior

Terminal output for the preview command is missing the --port option, despite it being in the _quarto.yml file.

quarto preview [...qmd file...] --no-browser --no-watch-inputs

For this image, this was the command (at the top of the terminal scroll not seen in image below):

quarto preview c:/dev/trinity-courses/110-essentials-of-computing-S24/lectures/lecture-7.1.qmd --to clean-revealjs --no-browser --no-watch-inputs

Your environment

• IDE: VSCode 1.87
• Quarto plugin: v1.111.0
• Windows: 11

Quarto check output

Quarto 1.4.550
[>] Checking versions of quarto binary dependencies...
      Pandoc version 3.1.11: OK
      Dart Sass version 1.69.5: OK
      Deno version 1.37.2: OK
[>] Checking versions of quarto dependencies......OK
[>] Checking Quarto installation......OK
      Version: 1.4.550
      Path: C:\Users\jonat\AppData\Local\Programs\Quarto\bin
      CodePage: 1252

[>] Checking tools....................OK
      TinyTeX: v2023.10
      Chromium: 869685

[>] Checking LaTeX....................OK
      Using: TinyTex
      Path: C:\Users\jonat\AppData\Roaming\TinyTeX\bin\windows\
      Version: 2023

[>] Checking basic markdown render....OK

[>] Checking Python 3 installation....OK
      Version: 3.12.2
      Path: C:/Users/jonat/AppData/Local/Programs/Python/Python312/python.exe
      Jupyter: 5.7.1
      Kernels: python3

[>] Checking Jupyter engine render....OK

[>] Checking R installation...........OK
      Version: 4.2.3
      Path: C:/PROGRA~1/R/R-42~1.3
      LibPaths:
        - C:/Program Files/R/R-4.2.3/library
      knitr: 1.42
      rmarkdown: 2.21

[>] Checking Knitr engine render......OK

Reproduce the VSCode preview using a project _quarto.yml containing project.preview.port and inspect the generated quarto preview command. Start from the command invocation described in the issue; done means the command includes --port 4200 and the preview uses that stable port for HTML or clean-revealjs output.