feat: AI task API, token-based context windows, SSH password auth, sudo bypass detection

Replace message-count context windows with token-budget based ones for both
studio and shell. Add /api/ai/task endpoint for background tool
check/install/update. Enhance sudo blocking to catch piped/chained elevation
commands. Add SSH password support via sshpass and connection editing UI.
Remove realTokens persistence in favor of consumption tracking. Bump to 0.4.1.

💘 Generated with Crush

Assisted-by: GLM-5.1 via Crush <crush@charm.land>

web/src/api/client.js

@@ -49,6 +49,7 @@ const api = {
   applyStarshipTheme: (theme) => request('/starship/apply-theme', { method: 'POST', body: JSON.stringify({ theme }) }),
   validateProvider: (provider) => request('/providers/validate', { method: 'POST', body: JSON.stringify(provider) }),
   runUpdate: (tool) => request('/update/run', { method: 'POST', body: JSON.stringify({ tool: tool || '' }) }),
+  aiTask: (task, tool) => request('/ai/task', { method: 'POST', body: JSON.stringify({ task, tool: tool || '' }) }),
   runCommand: (command, cwd) => request('/terminal', { method: 'POST', body: JSON.stringify({ command, cwd }) }),
   getTerminalSessions: () => request('/terminal/sessions'),
   addSSHConnection: (conn) => request('/terminal/sessions', { method: 'POST', body: JSON.stringify(conn) }),