add process, replays, more fs commands

[rgarcia]

• adds a bunch of new commands for API endpoints that either exist already (replays, filesystem) or will soon-exist (process, logs)
• adds a new pterm table that doesn't do the weird padding of row heights (makes browsers create output much nicer)

Some demos:

fs-demo.mp4

process-exec-demo.mp4

process-spawn-demo.mp4

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TL;DR

This PR significantly expands the kernel browsers command with new subcommands for managing processes, session replays, and filesystem operations within a browser instance. It also improves the CLI output with a custom table renderer.

Why we made these changes

To expose powerful new Kernel API features for process, replay, and filesystem management directly in the CLI. This gives users more granular, scriptable control over their browser instances and improves the overall user experience with better-formatted output.

What changed?

• New browsers Subcommands:
  • process: Execute and manage processes inside the VM (exec, spawn, kill).
  • replays: Create, list, and manage session replays.
  • fs: Full filesystem interaction (ls, cat, write, mkdir, download).
  • logs: Stream logs from a browser instance.
• Improved CLI Output:
  • Introduced a new custom table renderer (cmd/table.go) that removes unnecessary padding for a cleaner, more compact display.
  • Updated app list, app history, and browsers create to use the new table format.
• Enhanced Testing & Demos:
  • Added extensive unit tests for the new commands using testify and fake services.
  • Added new vhs tape demos for the new fs and process commands to showcase functionality.
• Core Improvements:
  • Refactored API error handling (pkg/util/errors.go) to be more robust in parsing error details from JSON responses.
  • Updated README.md with comprehensive documentation for all new commands.

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[Sayan-]

The tape stuff is very neat 👍

All the changes to the browsers cli lgtm. Blocking merge til we update the ref in go.mod but I think this is good to go, pending changes on the API side