Add `cortex history` command — show memory creation timeline by date

[KD-K2N2]

Description

Add a cortex history command that shows a chronological timeline of memory creation, grouped by date.

Expected behavior

$ cortex history --limit 20

March 22, 2026
  10:30 AM  [decision]   Using Fastify adapter for NestJS
  10:15 AM  [preference] Always use TypeScript strict mode
  09:45 AM  [context]    CDK stacks blocked on API keys

March 21, 2026
  04:20 PM  [thread]     Deepgram latency investigation
  02:10 PM  [decision]   Ghost Mode uses Swift sidecar

Flags

• --limit <n> — max entries (default 20)
• --project <name> — scope to project
• --type <type> — filter by memory type
• --json — JSON output

Good first issue

This is a great first contribution! The CLI pattern is well-established in packages/cli/src/index.ts. Look at the existing timeline command for reference.

[github-actions]

Welcome to Cortex! Thanks for opening your first issue.

Here are a few things that might help:

• Check the README for setup instructions
• Run cortex doctor --verbose and include the output if you're reporting a bug
• Browse existing discussions for ideas and Q&A

A maintainer will review this soon. We appreciate your contribution to making AI assistants smarter!