flow.rs: --verbose and reader silently ignored in 5 flow functions

[noahgift]

Bug

Five functions in flow.rs have underscore-prefixed parameters that silently discard user input:

1. print_decoder_only_flow() line 296: _verbose: bool
2. print_encoder_flow() line 379: _reader: Option<&AprReader>
3. print_encoder_block() line 394: _verbose: bool
4. print_decoder_flow() line 471: _reader: Option<&AprReader>
5. print_decoder_block() line 486: _verbose: bool

Root Cause

Parameters prefixed with underscores, silently discarded.

Expected Behavior

• --verbose should show per-layer tensor dimensions, weight statistics
• reader should be used to extract actual model data (shapes, dtypes)

Fix

Add warnings for unimplemented verbose/reader features.

Found via kaizen dogfooding audit.