consolidate getting started and other changes to improve user journey
General MR
Summary
Consolidated Getting Started into one canonical newcomer journey:
- Reworked the documentation landing page around user tasks instead of duplicating product marketing.
- Rebuilt Getting Started around choosing an evaluation, customer-managed, disconnected, or upgrade path.
- Moved the complete quickstart—without deleting its content—to Evaluation Quickstart.
- Retained the former quickstart URL as a compatibility forwarding page.
- Expanded First Customer-managed Deployment into a production-oriented checklist that delegates template-specific commands to the customer template.
- Narrowed Installation to environment-specific deployment patterns.
- Reordered navigation and corrected README entry points.
- Fixed broken multiline
quickstart.shcommands exposed during the move.
Relevant logs/screenshots
N/A
Linked Issue
Closes #3396 (closed)
Upgrade Notices
N/A