[Bug] No spinner after custom command - silent blocking at start

[randomm]

Problem

After typing a custom command like /start, there's a period of dead silence with no visual feedback. The spinner ("Thinking") should appear immediately after pressing Enter, but something is blocking before the spinner starts.

Expected

1. User types /start and presses Enter
2. Immediately: Spinner shows "Thinking"
3. When first chunk arrives: Spinner stops, content streams

Actual

1. User types /start and presses Enter
2. 5-10 seconds of nothing — blank screen, no spinner
3. Eventually content starts streaming

Context

• This is NOT the bootstrap/environment init (that's covered by "Setting up environment" spinner)
• This is NOT model loading (that happens before "Ready")
• This appears to be something blocking in the custom command processing path itself
• Regular chat messages may also have this issue but custom commands seem worse

Likely Causes

1. Blocking API call before the streaming generator starts yielding
2. Session/prompt construction doing synchronous work (file reads, context gathering)
3. Command parsing/resolution blocking on something
4. The spinner is started AFTER some blocking operation instead of BEFORE

Key Files to Investigate

• packages/opencode/src/cli/lite/index.ts — handleCustomCommand() function
• packages/opencode/src/cli/lite/commands.ts — handleCustomCommand()
• packages/opencode/src/cli/lite/session.ts — command() generator
• packages/opencode/src/command/ — Command execution path
• packages/opencode/src/session/ — Session prompt construction

Acceptance Criteria

• Spinner appears immediately (<100ms) after pressing Enter
• No blocking operations before spinner starts
• User has visual feedback that their input was received

[randomm]

Fixed by adding Command.list() to bootstrap Promise.all — command state now initializes during 'Setting up environment' spinner instead of on first /start.