docs: refresh recent feature coverage

[bifrost0x]

Summary

• synchronize the README with the features merged in Add terminal copy and paste shortcuts #44, Stop sending input when restoring sessions #45, Add Vietnamese localization #46, Add Tailscale SSH authentication #47, Harden SSH session lifecycle and cleanup #49, and Chain command set steps with shell-safe execution #51
• document terminal clipboard behavior, input-free session restoration, Tailscale SSH, and the complete post-connect command-set lifecycle
• clarify sudo handling, && boundaries between command-set steps, multiline free-text behavior, and upgrade compatibility
• replace the outdated command-library image and add a connection screenshot plus an end-to-end command-set GIF captured from a local instance
• refresh project-structure counts and fix the code-map caption typo

Validation

• pytest tests -q — 266 passed, 28 skipped
• node --test tests/js/command-set-utils.test.js — 5 passed
• all 32 local README references resolved successfully
• PNG/GIF formats, dimensions, frame count, and project-structure counts verified