feat: dock UX redesign, stdin write, command refactoring

[aliou]

Summary

• Add log dock component for viewing process output
• Add stdin write action for interactive processes
• Split commands into separate files for maintainability

Changes

Dock UX Redesign

• Add /ps:dock, /ps:focus, /ps:logs commands
• New DockStateManager for centralized dock state
• New LogDockComponent for interleaved process logs view
• Preserve ANSI colors in process output
• Fix duplicate notifications

Stdin Write Action

• Add write action to process tool for writing to process stdin
• Support interactive processes that accept user input

Command Refactoring

• Split commands from index.ts into separate files
• Each command in its own file (ps-command.ts, ps-kill-command.ts, etc.)
• Shared utilities in completions.ts and pick-process.ts

Testing

• Run pnpm typecheck and pnpm lint - all pass
• Manual testing of dock commands and process management