Clarify and expand the usage comments in bootstrap.ps1: add a "Quick start (no arguments)" note and a recommended "With arguments" workflow that shows saving the script locally and invoking it with -dev and -file parameters. Reformat example commands for clarity; no functional code changes.
Add -file argument handling and automatic .js extension, allowing the script to locate and run app.js via cscript (interactive) when provided. Improve argument parsing to support -dev and -file together, surface file/branch choices in logs, and reorganize steps/messages for clearer temporary workspace, download, extraction, and execution flow. Default bootstrap behavior remains (launch bootstrap.bat non-blocking), with updated success/failure reporting.
Remove the param block and rename DefaultBranch to $defaultBranch. Add argument parsing for iex-compatible invocations (e.g. `iex -dev main`, `iex main`, or no args) by inspecting $args and selecting the branch accordingly, then log the chosen branch. Simplify branch handling and build the GitHub ZIP download URL using the resolved branch. Small cleanup and reordering of steps to accommodate the new parsing logic.
