Complete machine-readable CLI output

[zhou-wang-git]

What changed

• add machine-readable output to init and capture
• return structured JSON usage and runtime errors
• reject unknown and extra inspect and verify arguments
• document the published npm Quick Start and JSON/exit-code contract

Why

BugBundle's automation contract was incomplete: some commands supported JSON while init, capture, and error paths still emitted plain text. Loose argument parsing could also silently accept invalid invocations.

This makes the CLI predictable for scripts and AI tools while preserving existing human-readable output.

Impact

• normal CLI output remains unchanged
• --json callers receive parseable stdout on success and structured stderr on failure
• invalid options and extra bundle paths now exit with code 2 instead of being ignored

Validation

• pnpm check
• pnpm build
• real capture/verify dogfood with exit-code capture, secret redaction, ZIP content scan, and integrity verification