Fix Windows/WSL startup and Bash completion stalls

[im10furry]

Fixes #96.

This PR reduces avoidable blocking on the interactive startup path and hardens Bash subprocess handling on Windows/WSL.

Main changes:

• Move update checking out of the REPL render critical path.
• Defer GPT-5 profile repair until the first prompt input is ready.
• Cache parsed global config after \enableConfigs()\ and update the cache after successful saves.
• Avoid repeated global config reads in \saveGlobalConfig()\ just to preserve \projects.
• Spawn foreground shell commands with stdin ignored instead of inherited.
• Use Windows \overlapped\ stdout/stderr pipes for shell subprocesses.
• Add \KODE_STARTUP_PROFILE-gated timings for config I/O, update checks, query prep, Bash result finalization, and model config saves.
• Keep CLI flags, output protocols, and command behavior unchanged.

Validation

Automated checks:

• \run typecheck\
• \run lint\
• \ test\
  • 546 pass
  • 8 skip
  • 0 fail
• \�un run build:npm\

Focused tests added/updated:

• Config cache behavior
• Shell stdio selection on Windows/non-Windows
• Slow Windows-sensitive test timeouts for UNC/LSP checks

Real WSL validation:

• Environment: WSL 2.6.3, Debian WSL2
• Verified Windows-side CLI subprocess path executing WSL commands through project \BunShell\ and \BashTool.
• \wsl -d Debian -- printf ok\
  • cold run about 2.2-2.4s
  • warm runs about 0.2-0.8s
• \sleep 5 & echo done\ did not wait for the background sleep and did not show a 10s tail.
• Large stdout (\seq 1 500) returned normally.

Notes

The update banner may now appear after the initial UI render instead of before it. The displayed text is unchanged; only the timing is different so startup is not blocked by npm/registry checks.