[bug] cli: unknown flags are silently ignored instead of rejected #59

Split from #50 (item 8).

Summary

The argument parser (crates/meshloop-cli/src/args.rs) looks up known flags with flag_value and has_flag and ignores everything else. A typo or an unsupported flag is accepted without any message. For example, status --config x --db y drops both flags (args.rs:255), which is part of the cause of #46.

Expected

• Each subcommand checks its arguments against the flags it defines and rejects anything else. The error names the flag and the subcommand, and exits non-zero (ok: false with --json).
• Global flags such as --json and the origin flags stay accepted on every subcommand.

Relations

Touches the same parsing code as #46, which adds --config and --db to status. Land #46 first, or include its flag additions here, to avoid conflicts.

Acceptance criteria

• Test: status --bogus → non-zero exit, and the message names --bogus and status.
• Test: every subcommand's documented flags still parse. A table-driven test over the command list is enough.
• Test: global flags are accepted on every subcommand.

🤖 Generated with Claude Code