[FEATURE] Prompt suggestions should incorporate memory files and CLAUDE.md context

Preflight Checklist

• [x] This is a single feature request (not multiple features)
• [ ] I have searched existing requests and this feature hasn't been requested yet

Problem Statement

The grayed-out prompt suggestions currently source from git history and conversation history. It would be
valuable if they also pulled from memory files and CLAUDE.md — e.g., suggesting common commands or referencing
active plans.

Proposed Solution

Allow prompt suggestions to read from memory files and CLAUDE.md in addition to git history and conversation
context. This would make suggestions contextually relevant to the project's workflows, conventions, and active
work tracked in memory.

Alternative Solutions

_No response_

Priority

High - Significant impact on productivity

Feature Category

CLI commands and flags

Use Case Example

I have a CLAUDE.md with a "Common commands" table and memory files tracking active plans. When I start typing in
the input, the prompt suggestions show generic git-history-based hints instead of project-relevant ones like
"continue the Phoenix token swap plan" or "run typecheck on mobile-bff".

Additional Context

_No response_