Code Quality & Cleanup (from TODO.md)

In this issue we track possible Code Quality & Cleanup Items from TODO.md

Code Quality & Cleanup

P1 - High Priority

• - [P1, large] Make coding style more uniform (e.g. docstrings)
• - [P1, large] Reduce code size

P2 - Medium Priority

• - [P2, small] Avoid most inline imports: fixed #113
• - [P2, medium] Break cycles by moving things to their own file if necessary fixed #113
• - [P2, medium] Unify or align or refactor VectorBase and EmbeddingIndex
• - [P2, medium] Address TODO comments (too numerous)
• - [P2, medium] Address raise NotImplementedError("TODO") (five found) -- implement it

P3 - Low Priority

• - [P3, medium] Change inconsistent module names (Claude uses different naming style)
• - [P3, medium] Rewrite podcast parsing without regexes
• - [P3, medium] Switch from Protocol to ABC
• - [P3, medium] Reduce duplication between ingest_vtt.py and typeagent/transcripts/
• - [P3, small] Rename kplib.py to something ending in _schema.py

Start with TODO.md and choose a single unchecked cleanup item; the issue names VectorBase, EmbeddingIndex, ingest_vtt.py, typeagent/transcripts/, and kplib.py as investigation points. Define the selected item's scope and completion checks before changing code, then verify that the corresponding cleanup is complete without expanding into the other listed tasks.