Make pipeline init interactive with user prompts instead of TODO placeholders

[Copilot]

The clarifai pipeline init command previously created pipeline structures with placeholder values and TODO comments that required manual editing across multiple nested files. This made the initialization process tedious and error-prone.

Changes Made

This PR transforms the pipeline initialization into an interactive experience that prompts users for all required information upfront:

$ clarifai pipeline init
Welcome to Clarifai Pipeline Initialization!
Please provide the following information:
User ID: my-user
App ID: my-app
Pipeline ID [hello-world-pipeline]: awesome-pipeline
Number of pipeline steps [2]: 3
Name for step 1 [stepA]: data-ingestion
Name for step 2 [stepB]: text-processing  
Name for step 3 [stepC]: model-inference

Creating pipeline 'awesome-pipeline' with steps: data-ingestion, text-processing, model-inference

Key Improvements

• Interactive prompts: Users provide user_id, app_id, pipeline_id, number of steps, and step names during initialization
• Dynamic step creation: Supports any number of pipeline steps with custom names (defaults to 2 steps: stepA, stepB)
• Clean generated files: All configuration files contain actual user-provided values instead of placeholder text
• No manual editing required: Eliminates all TODO comments in configuration files
• Backward compatibility: Provides sensible defaults so users can accept defaults by pressing Enter

Before vs After

Before: Generated config.yaml with placeholders

pipeline:
  id: "hello-world-pipeline"  # TODO: please fill in
  user_id: "your_user_id"  # TODO: please fill in
  app_id: "your_app_id"  # TODO: please fill in

After: Generated config.yaml with actual values

pipeline:
  id: "awesome-pipeline"
  user_id: "my-user"
  app_id: "my-app"
  step_directories:
    - data-ingestion
    - text-processing
    - model-inference

This change significantly improves the developer experience by providing a streamlined initialization workflow that's ready to use immediately without manual configuration file editing.

Fixes #767.

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[zeiler]

this number 2 is still valid, the user has to update the logic of each step in it's {step_dir}/1/pipeline_step.py

[zeiler]

the user still has to enter the compute_info they want each step to consume into the config.yaml

[github-actions]

Package	Line Rate	Health
clarifai	43%	❌
clarifai.cli	41%	❌
clarifai.cli.templates	36%	❌
clarifai.client	68%	➖
clarifai.client.auth	67%	➖
clarifai.constants	100%	✔
clarifai.datasets	100%	✔
clarifai.datasets.export	80%	✔
clarifai.datasets.upload	75%	➖
clarifai.datasets.upload.loaders	37%	❌
clarifai.models	100%	✔
clarifai.modules	0%	❌
clarifai.rag	72%	➖
clarifai.runners	52%	➖
clarifai.runners.models	60%	➖
clarifai.runners.pipeline_steps	44%	❌
clarifai.runners.pipelines	80%	✔
clarifai.runners.utils	63%	➖
clarifai.runners.utils.data_types	72%	➖
clarifai.schema	100%	✔
clarifai.urls	60%	➖
clarifai.utils	57%	➖
clarifai.utils.evaluation	67%	➖
clarifai.workflows	95%	✔
Summary	62% (7879 / 12742)	➖

Minimum allowed line rate is 50%