feat(memory): Agent Prompts for Storage

[acreeger]

Parent: #318

Requirements

1. Update session summary prompt to instruct Claude to include project context:
   • Project name
   • Project description/purpose
   • Tech stack
   • Domain
2. This context enables semantic search to match related projects across repos
3. Context should be naturally woven into summary, not a separate section

Rationale

Without project context in stored memories, cross-repo recall would surface irrelevant results. By including "this is an e-commerce Node.js API" in the summary, searches from related projects will match.

Acceptance Criteria

• Summary prompt updated with project context guidance
• Generated summaries include project context
• Context is useful for semantic matching (not just metadata dump)