docs: rewrite README with install commands and full command reference

[juhovainio]

Summary

• Replaces the old quick-start with direct nightly download commands for Linux/WSL and Windows (no installer scripts)
• Adds a quick reference table covering the most common commands
• Documents all public commands with subcommands and key flags, grouped by area (installation, runtimes, engines, serving, dashboard, chat, ComfyUI, automations, config, logs/cleanup)
• Notes that only nightly builds are available at this time
• Removes references to stale docs (implementation audit, plans/)

Test plan

• Read through rendered README on GitHub and verify formatting
• Verify download URLs resolve to the correct release assets

[volen-silo]

Really nice rewrite — much clearer, and I cross-checked the command reference against the clap definitions, almost all of it matches exactly. 🎉

A couple of small things:

• automations enable --mode: docs say auto|review, but the actual accepted values are observe|propose|contained (WatcherModeArg in apps/rocm/src/main.rs). The current values would error out, so worth fixing.
• Minor: serve --device also accepts gpu_preferred (not just gpu_required|cpu_only), and install sdk has a --prefix flag that might be worth surfacing since the intro talks about choosing an install folder.

Otherwise everything checks out. Only other thing is the nightly download URLs (rocm / rocm.exe) — just worth confirming those assets actually publish on the nightly release before merge (already in your test plan). Thanks for doing this! 🙌