refactor: centralize error handling with typed error classes

[wyattjoh]

What

• Introduce a typed error hierarchy (CliError, UserAbortError, ApiError, BapiError, PlapiError) in src/lib/errors.ts with standardized exit codes
• Add a single top-level error handler in cli.ts that catches all typed errors and formats output consistently
• Add --verbose flag for detailed API error output
• Add SIGINT handler that exits with code 130
• Add oxlint configuration (.oxlintrc.json)

Why

Error handling was scattered across every command — each had its own try/catch + console.error + process.exit with inconsistent formatting, exit codes, and messaging. This made it difficult to maintain consistent UX and meant every new command had to reimplement error handling. Centralizing it ensures uniform behavior and reduces per-command boilerplate.

How

• Created src/lib/errors.ts with a class hierarchy: CliError for general CLI errors, ApiError (with BapiError/PlapiError subclasses) for HTTP failures, and UserAbortError for prompt cancellations. Helper functions usageError() and userAbort() provide ergonomic throwing.
• Wrapped program.parseAsync() in a main() function with a centralized catch that dispatches on error type — clean exit for aborts, red-formatted messages for CLI errors, labeled API error details for API failures.
• Updated all commands to throw typed errors instead of handling exits locally.
• Updated all tests to assert on thrown errors rather than spying on process.exit.

AIE-626

[brkalow]

consider making this a method on ApiError

[brkalow]

Looks good, do you think there are any meaningful additions to AGENTS.md to be made to ensure this pattern is followed?