docs: add Linux troubleshooting for menu freeze, path-sandbox, and AVX issues

[GautamKumarOffical]

Summary

Adds Linux troubleshooting documentation for known issues.

Closes #775, #767, #797

What this PR does

Creates a new LINUX.md file documenting known Linux-specific issues and workarounds:

• CLI menu freeze on Enter (Bug: CLI interactive menu freezes on Enter/Submit on Linux (KDE Konsole / Node LTS) #775): Workarounds for KDE Konsole and other terminals
• Path-sandbox error for skills (Bug: Path-sandbox [FILE_OUTSIDE_PROJECT] error when executing skills referencing auxiliary files #767): Explanation and workaround for FILE_OUTSIDE_PROJECT error
• SIGILL on older CPUs (linux-x64-baseline target still contains AVX instructions, causing SIGILL on older CPUs (SSE4.1 only) #797): Explanation of AVX instruction issue in baseline builds

Why this helps

Linux users encountering these issues now have clear documentation and workarounds instead of having to search through GitHub issues.

Hi! Just to confirm, the linux-x64-baseline binary indeed crashes with SIGILL on older CPUs because it still contains AVX and even AVX-512 instructions (like vinserti128 and %zmm registers).

For reference, my CPU flags only support up to SSE4.1: flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl cpuid aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm pti tpr_shadow flexpriority vpid dtherm vnmi (No avx, avx2 or avx512 support).

Compiling the baseline target with Bun using a truly generic x86-64 target (without AVX) is necessary for older hardware to run the tool.

Thanks for pulling together troubleshooting notes for these three issues — consolidating known Linux gotchas into one doc instead of scattered GitHub issues is genuinely useful, and the WINDOWS.md addition for #789 is a nice bonus in the same spirit.

A few things to tighten before this is portable:

1. Verify claims against the actual issues. For Bug: Path-sandbox [FILE_OUTSIDE_PROJECT] error when executing skills referencing auxiliary files #767 (path-sandbox), the "workaround: copy skill files into your project directory" and the stated cause ("SDK's path validation blocks reads outside the project root") need to match what was actually said/fixed in the issue thread. If the real fix was a config flag or an allowlist entry rather than manually copying files, this doc will mislead users.
2. linux-x64-baseline target still contains AVX instructions, causing SIGILL on older CPUs (SSE4.1 only) #797 AVX/SIGILL section is speculative — "may still contain AVX instructions due to Bun's compilation" and "wait for a fix" isn't actionable. If there's a known status (fixed in a later release, tracked upstream in Bun, etc.), that should be stated instead of a vague waiting game.
3. Bug: CLI interactive menu freezes on Enter/Submit on Linux (KDE Konsole / Node LTS) #775 terminal freeze fixes (GNOME Terminal/Alacritty/Kitty recommendations, tmux workaround) read like plausible guesses rather than confirmed workarounds from the issue. Worth quoting or linking the specific comment that confirmed the fix, if one exists.

Since this is a docs PR, the bar is factual accuracy tied to the referenced issues, not just plausible-sounding troubleshooting steps. If you can confirm each workaround against maintainer/user replies in #775, #767, #797 (or link the exact comment), this becomes a straightforward merge.

Marking this stale - there has been no activity here for 66 days. It will close in 7 days unless someone comments.

This is backlog upkeep, not a verdict on the pull request. A single comment keeps it open, and anything closed this way can be reopened.

Apologies — this PR was auto-closed by GitHub when we force-pushed a history rewrite of this repository (repository maintenance; every commit SHA changed). That was not a judgment on this PR, and GitHub does not allow us to reopen it because the commits it was based on no longer exist in the new history.

If you'd like to continue with this change: rebase your branch onto the new main (or recreate it from a fresh clone) and open a new PR — feel free to link back to this one for context, and we'll pick up the review there.

Sorry for the churn, and thanks for contributing.