Support more subcommands and arguments in tectonic -X watch --exec especially on VSCode

[KagaJiankui]

I'm trying to use the V2 CLI tectonic -X watch --exec compile on VSCode. Under three different contexts, the CLI gives out three different abnormalities:

1. If tectonic -X watch --exec compile is invoked in a seperate Powershell7 terminal running in Windows Terminal, it runs forever into a deadloop due to the change made to intermediate file filename.aux. Designating "compile src/filename.tex -o build/filename --hide build/filename/filename.aux" or "--keep-intermediates" gives the relief.
2. If tectonic -X watch --exec "compile ./src/${filename.tex}" is invoked by VSCode tasks, tectonic complaining about

   error: unexpected argument './src/filename.tex' found
   Usage: watch [OPTIONS]
   For more information, try '--help'.
   

3. This is the most strange part. Either invoke the tectonic -X watch --exec compile without any arguments provided to compile by task or in VSCode terminal (with "terminal.integrated.persistentSessionReviveProcess": "never" configured), tectonic complain about

   [Running `"tectonic.exe" -X compile ./src/report_lab2.tex --keep-intermediates --synctex -o ./build/report_lab2`]
   'tectonic.exe' 不是内部或外部命令，也不是可运行的程序
   或批处理文件。
   [Finished Running. Exit Status: 1]
   

But if launch VSCode from Powershell in (1), the command works again magically, only when invoked in VSCode Terminal. Echoing the environment variables to a txt and compare them in VSCode tells no difference.

Directory Structure

+---.vscode
|       tasks.json
|
+---build
|   \---filename
|           filename.aux
|           filename.log
|           filename.pdf
|           filename.synctex.gz
|
\---src
    |   listingset.tex
    |   filename.pdf
    |   filename.tex
    |
    \---index.assets
            20240303235337.png
            20240303235723.png

listingset.tex and contents of index.assets are dependencies required by filename.tex, which contains no \write18.

VSCode Tasks

Erroneous

    {
      "label": "Tectonic - Watch", // This one does not work
      "type": "shell",
      "command": "tectonic",
      "isBackground": true,
      "args": [
        "-X",
        "watch",
        "--exec",
        "\"compile",
        "./src/${fileBasenameNoExtension}.tex",
        "-o",
        "./build/${fileBasenameNoExtension}\""
        // "-x",
        // "--print"
      ],
      "group": {
        "kind": "build",
        "isDefault": true
      },
      "presentation": {
        "reveal": "silent"
      },
      "options": {
        "cwd": "${workspaceFolder}"
      },
      "problemMatcher": {
        "owner": "LaTeX",
        "fileLocation": [
          "autoDetect",
          "${workspaceFolder}/src"
        ],
        "pattern": [
          {
            "regexp": "^(info|note|warning|error):\\s?(.*\\.(tex|cls|bib|sty)):(\\d+):(\\d*)\\s?(.*)$",
            "file": 2,
            "line": 4,
            "endColumn": 5,
            "severity": 1,
            "message": 6
          }
        ],
        "background": {
          "activeOnStart": true,
          "beginsPattern": "^\\[Running `tectonic\\.exe -X .+`\\]",
          "endsPattern": "^\\[Finished.*Status: \\d+\\]"
        }
      }
    }

Working

{
      "label": "Tectonic - Compile", // This one works
      "type": "shell",
      "command": "tectonic",
      "isBackground": true,
      "args": [
        "-X",
        "compile",
        "--synctex",
        "--keep-intermediates",
        "--keep-logs",
        "./src/${fileBasenameNoExtension}.tex",
        "-o",
        "${workspaceFolder}/build/${fileBasenameNoExtension}"
      ],
      "group": {
        "kind": "build",
        "isDefault": true
      },
      "presentation": {
        "reveal": "silent"
      },
      "options": {
        "cwd": "${workspaceFolder}"
      },
      "problemMatcher": {
        "owner": "LaTeX",
        "fileLocation": [
          "autoDetect",
          "${workspaceFolder}/src"
        ],
        "pattern": [
          {
            "regexp": "^(info|note|warning|error):\\s?(.*\\.(tex|cls|bib|sty)):(\\d+):(\\d*)\\s?(.*)$",
            "file": 2,
            "line": 4,
            "endColumn": 5,
            "severity": 1,
            "message": 6
          }
        ],
        "background": {
          "activeOnStart": true,
          "beginsPattern": "^\\[Running `tectonic\\.exe -X .+`\\]",
          "endsPattern": "^\\[Finished.*Status: \\d+\\]"
        }
      }
    }