feat: add stdin support for file options

[ejseqera]

This PR adds support for reading file content from stdin using the - convention for file-based options in pipeline launch commands.

What's Changed

Users can now pass - as the value for any file option to read content from stdin instead of a file path:

• --params-file - - Read pipeline parameters from stdin
• --config - - Read Nextflow config from stdin
• --pre-run - - Read pre-run script from stdin
• --post-run - - Read post-run script from stdin

For example:

# Pass parameters via pipe
echo '{"genome": "GRCh38"}' | tw launch my-pipeline --params-file -

# Pass config via heredoc
tw launch my-pipeline --config - <<EOF
process {
    executor = 'awsbatch'
    queue = 'my-queue'
}
EOF

# Pass pre-run script from stdin
cat setup.sh | tw launch my-pipeline --pre-run -

# Chain with other commands
curl https://example.com/params.json | tw launch my-pipeline --params-file -