feat(plugin/telegram_bot): replace bare prompts with 5-step guided setup wizard
Step 1 — create bot via @BotFather (instructions + press-any-key pause)
Step 2 — find Telegram user ID via @userinfobot (instructions + pause)
Step 3 — set session passphrase with security explanation
Step 4 — save all three vault keys, print ✓ confirmations
Step 5 — configuration complete marker
Adds setup cancellation on empty token, updated tests: happy path, mismatch,
and cancel all covered; press_any_key_to_continue calls properly patched.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>