feat: automated session compaction and archiving system for Amazon Q CLI

## Problem

During long development sessions, context windows fill up and we lose track of what we've accomplished and learned. We need a way to compact and preserve important context.

## Proposed Solution

Create a prompt that can be invoked when context gets full to:
- Run Amazon Q's `/compact [optional prompt]` over the current context
- Generate a meta-flywheel-changelog-ai style summary
- Preserve key insights and decisions for future reference

## Implementation Ideas

- Simple prompt that triggers context compaction
- Could use `/compact` command or ask Q to summarize key points
- Store results in a way that's easy to reference later
- Manual invocation when context window is getting full

## Success Criteria

- [ ] Easy to invoke when context is full
- [ ] Preserves important insights and decisions
- [ ] Integrates cleanly with current workflow
- [ ] Helps maintain continuity across long sessions

The issue names no file or test; start by locating the repository's Amazon Q CLI prompt or command configuration and reviewing how `/compact` is invoked. Then determine where summaries should be stored and how manual invocation fits the current workflow. Done means the four listed success criteria are demonstrably met.

Written by the indexing model from the issue text.