Add progress bar for large repos (100+ files)

[Nehal-cell]

Problem

On large repos, CodeMorph runs silently for several minutes during intent extraction and migration. Users don't know if it's working or stuck.

Solution

Use the existing Rich library to add a progress bar showing:

• Current stage (Analysing / Building IntentGraph / Migrating)
• Files processed vs total
• Estimated time remaining

Example

Migrating files...  ████████░░░░░░░░  12/42 files  (est. 4 min remaining)