feat(docs): add CAIPE product tour

[sriaradhyula]

Description

Refreshes the CAIPE OSS website with a first-party product tour of the new Web experience.

• Adds a privacy-clean 14.8-second product preview in WebM and MP4 with a static poster.
• Highlights Home, global search, harness-aware agent selection, workflows, schedules, appearance, and notifications.
• Keeps the longer Vidcast demo as a secondary action.
• Pauses autoplay for reduced-motion users and retains native playback controls.
• Updates the homepage and feature catalog with explicit preview language.
• Documents Dynamic Agents backward compatibility while Harness Engine adapters reach parity.

Related work: #2392, #2401, #2407, #2408, #2416.

Type of Change

• New Feature
• Documentation

Validation

• npm run typecheck
• npm run build
• Browser verification of video playback, WebM/MP4 fallbacks, poster, Home layout, and feature catalog
• Media inspection: 1280x720, 30 fps, 14.8 seconds, muted, no PII or internal hostnames

Checklist

• I have read the contributing guidelines
• Existing issues have been referenced where applicable
• I have verified this change is not present in other open pull requests
• Functionality is documented
• All code style checks pass
• New behavior is covered by build and browser validation
• All relevant tests pass

[github-actions]

✅ No proprietary content detected. This PR is clear for review!

[sriaradhyula]

Visual preview

The homepage embeds a 14.8-second muted loop with WebM and MP4 fallbacks. The captured preview masks the user identity and contains no internal hostname or personal data.

[sibuthomasmathew]

Moving to draft because documented feature in #2401 hasn't been reviewed and merged yet