[FEATURE] Add epoch-level progress bar to full trainer

[eliasgomes]

When training with nam-full, only a per-batch progress bar is shown, making it hard to tell overall training progress across epochs. This adds a second Rich progress bar below the existing one that tracks epoch completion with elapsed and remaining time estimates.

Before

After

Changes

• Add _EpochProgressBar callback extending RichProgressBar with a separate epoch-level progress bar
• Add _EpochCountColumn for epoch count display using Lightning's N/max-1 convention
• Use transient Rich Progress for clean terminal output on both normal completion and Ctrl+C interruption
• Remove v_num from displayed metrics (always 0 for single-logger setups)
• Show just Epoch N on the per-batch bar (total is redundant with the epoch bar)
• Add unit tests for both new classes

[sdatkinson]

This is a cool idea.

I'd like to support this--but optionally. I could've sworn I'd implemented the ability to add callbacks via the configuration (i.e. the learning.json).

So you could make my_package.my_module.MyCallback, and then in learning.json, add:

"callbacks": [
  {
    "name": "eliasgomes_package.nam.EpochProgressBar",
    "args": [],
    "kwargs": {}
  }
]

(probably under the "trainer" field as you've put "enable_progress_bar".)

And it'd initialize and append this (and maybe others) using nam.util.init.

If you want to PR me that then you can use your progress bar and I can put in other things I like 😉