Add command aliases for common alternative names

[iamfj]

Problem

AI models frequently attempt to use linearis issues get <id> instead of the correct linearis issues read <id>. This causes confusion and failed commands:

$ linearis issues get DAT-913
error: too many arguments for 'issues'. Expected 0 arguments but got 2.

The error message doesn't hint at the correct command name either, making recovery harder for agents.

Proposal

Introduce command aliases for subcommands where alternative names are intuitive. Commander.js supports this via .alias() / .aliases().

Examples:

• issues read → alias get, show
• Other domains could follow the same pattern where applicable (e.g., list → ls)

Benefit

• Reduces failed commands for LLM agents consuming the CLI
• No breaking changes — existing commands remain unchanged
• Minimal implementation effort (one .alias() call per subcommand)