Add CLI command to pre-download models

[titusz]

Problem

There's no explicit way to pre-download the models without writing Python code. This makes it difficult to:

• Pre-download models in container builds
• Cache models in CI/CD pipelines
• Ensure models are available before running the application
• Verify model integrity explicitly

Current Workaround

Users must write custom Python code:

import iscc_sct.code_semantic_text as sct
import iscc_sct.utils as sct_utils

# Trigger download
sct.model()
# or
sct_utils.get_model()

This is not intuitive and requires understanding the internal API.

Expected Behavior

Add a CLI command to explicitly download and verify models:

# Download all models
iscc-sct download-models

# Verify models are present and valid
iscc-sct verify-models

# Show model information
iscc-sct model-info

Example Output

$ iscc-sct download-models
Downloading ONNX model (iscc-sct-v0.1.0.onnx)...
  URL: https://github.com/iscc/iscc-sct/releases/download/v0.1.0/iscc-sct-v0.1.0.onnx
  Size: 435 MB
  Progress: ████████████████████ 100%
  Checksum: ✓ Verified (BLAKE3)
  Location: /home/user/.local/share/iscc-sct/iscc-sct-v0.1.0.onnx

Downloading tokenizer model...
  ✓ Complete

All models downloaded successfully.

$ iscc-sct verify-models
✓ ONNX model: OK
✓ Tokenizer model: OK

$ iscc-sct model-info
ONNX Model:
  Version: v0.1.0
  Path: /home/user/.local/share/iscc-sct/iscc-sct-v0.1.0.onnx
  Size: 435 MB
  Checksum: valid

Tokenizer Model:
  Path: /home/user/.local/share/iscc-sct/tokenizer
  Size: 1.2 MB

Use Cases

Container Builds

# Pre-download models during build
RUN iscc-sct download-models

CI/CD

- name: Setup models
  run: iscc-sct download-models

- name: Verify models
  run: iscc-sct verify-models

User Scripts

#!/bin/bash
# Ensure models are available before starting app
iscc-sct verify-models || iscc-sct download-models
python app.py

Implementation

Add new commands to the existing sct CLI:

import typer
from iscc_sct import utils

app = typer.Typer()

@app.command()
def download_models():
    """Download all required models."""
    typer.echo("Downloading models...")
    utils.get_model()
    # Download tokenizer if needed
    typer.echo("All models downloaded successfully.")

@app.command()
def verify_models():
    """Verify all models are present and valid."""
    try:
        if not utils.MODEL_PATH.exists():
            raise FileNotFoundError("ONNX model not found")
        if not utils.check_integrity(utils.MODEL_PATH, utils.MODEL_CHECKSUM):
            raise ValueError("ONNX model integrity check failed")
        typer.echo("✓ All models verified")
    except Exception as e:
        typer.echo(f"✗ Verification failed: {e}", err=True)
        raise typer.Exit(1)

@app.command()
def model_info():
    """Show information about downloaded models."""
    # Display model paths, sizes, versions, etc.
    pass

Benefits

• Clear, explicit way to manage models
• Better user experience
• Simplifies container and CI/CD workflows
• Follows CLI best practices
• Makes model management transparent