feat: Add posthog continuous ai guide

[BekahHW]

Description

closes CON-3884
[ What changed? Feel free to be brief. ]
This pull request adds a new guide to the documentation overview, expanding the resources available for users interested in analyzing user behavior data.

Documentation update:

• Added a link to the new guide, "PostHog Session Analysis with Continue CLI," in docs/guides/overview.mdx. This guide helps users analyze user behavior data and optimize their codebase with automatic issue creation.

AI Code Review

• Team members only: AI review runs automatically when PR is opened or marked ready for review
• Team members can also trigger a review by commenting @continue-general-review or @continue-detailed-review

Checklist

• I've read the contributing guide
• The relevant docs, if any, have been updated or created
• The relevant tests, if any, have been updated or created

Screen recording or screenshot

[ When applicable, please include a short screen recording or screenshot - this makes it much easier for us as contributors to review and understand your changes. See this PR as a good example. ]

Tests

[ What tests were added or updated to ensure the changes work as expected? ]

---

Summary by cubic

Added a new guide that shows how to automate PostHog session recording analysis and open actionable GitHub issues. Linked the guide from the guides overview.

• New Features
  • New guide: PostHog Session Recording Analysis with Continue CLI
  • Ready-to-run scripts to fetch sessions, analyze patterns, and create issues
  • Daily workflow via GitHub Actions, plus cron and local options
  • Setup, testing, security best practices, and advanced extensions