Add support for Gemini meeting transcripts in addition to meeting notes

[eshulman2]

Description

Support direct input of Google Meet transcripts generated by Gemini in addition to manually written meeting notes.

Current Limitation

The system currently processes meeting notes from Google Docs/Calendar.
Users must manually create meeting notes before action items can be generated.
Additionally transcript might have additional context useful for creating the action items

Technical Considerations

API Access

• Requires Google Meet API access
• May need additional OAuth scopes for transcript access
• Handle cases where transcripts aren't available

Transcript Format

• Parse Gemini transcript structure (speaker labels, timestamps)

Performance

• Transcripts can be very long (>10k tokens)
• May need chunking strategy (see Issue refactor: major architecture improvements and human-in-the-loop workflow #6)
• Cache transcript content in Redis

Acceptance Criteria

• Google Meet transcript fetching implemented
• Transcript parsing handles speaker labels and timestamps
• Combine meeting notes with transcript context
• Handle meetings without transcripts gracefully
• Handle meetings without meeting notes gracefully
• Tests for all three processing modes
• Documentation updated with examples for each mode

Priority: 🟡 Medium
Effort: 6-8 hours
Difficulty: Medium-High
Dependencies: Requires Google Meet API access