feat(terminal): confirm-to-fill sudo password hint (#1281)

Rework sudo password autofill from auto-fill to a Tabby-style hint + Enter to confirm. When a sudo command is armed and a password prompt appears, show a dimmed inline hint instead of sending the password; Enter pastes the saved password and submits, any other key dismisses it.

Confirmation removes the credential-leak class (nothing is sent without the user pressing Enter at a visible hint), so detection is relaxed to a broad match (Ubuntu/PAM bare "Password:", "[sudo] password for…", localized prompts) and the per-host toggle is removed — always available when the host has a saved password.

Safety guards:
- don't arm when the hint can't render (no overlay) so Enter isn't silently intercepted;
- swallow Escape/Backspace so the byte never reaches the no-echo prompt;
- clear the pending hint once output moves past the prompt (sudo timeout/failure/returns to shell) so a later Enter can't leak the password to the shell.

Implementation ~140 lines; full suite green; manually verified on a real Linux host.

domain/models/connection.ts

@@ -140,7 +140,6 @@ export interface Host {
   serialConfig?: SerialConfig;
   // SFTP specific configuration
   sftpSudo?: boolean; // Use sudo for SFTP operations (requires password)
-  terminalSudoAutoFill?: boolean; // Auto-fill sudo password prompts in terminal output
   sftpEncoding?: SftpFilenameEncoding; // Filename encoding for SFTP operations
   sftpBookmarks?: SftpBookmark[]; // Bookmarked SFTP paths for quick navigation
   // Managed source: if this host is managed by an external file (e.g., ~/.ssh/config)