Read clearer CLI errors with the next step

Every message the CLI prints now says what failed, names the file, ID or URL involved, and gives the next step on a hint: line, so a failed command tells you how to fix it.

• Improved errors across every command: server errors show the server's message instead of raw responses, procedure.yaml errors point to the line and column with "did you mean" suggestions, and the installers name the URL that failed.
• Added -v, -q and --color flags, with NO_COLOR support, and moved diagnostics behind -v for quieter output.
• Updated output for scripts and agents: --json goes after the subcommand on the commands that return data, every error is one JSON object, and exit codes now mean something (2 usage error, 4 not found, 6 not logged in). Scripts that relied on the old exit code 1 or on message text need updating.