feat: add file support to stacks-inspect commands

[simone-stacks]

Some contrib/stacks-inspect commands that process encoded data (transactions, blocks, etc...) have inconsistent input handling - some only accept hex strings as arguments, others only file paths. This limits flexibility for scripting and piping workflows.

I think we should add unified file and stdin support to those commands, following the same convention used in contrib/clarity-cli:

• "-" reads from stdin
• File path reads from file
• Direct value as fallback (backward compatible)