docs: add OSS-vs-Platform comparison, drop Learn More section

Reframe the Open Source section to clarify what HolmesGPT OSS is
(CLI/HTTP API only) and what the Robusta Platform adds (web UI,
Slack/Teams bots, automatic alert triage and grouping).

Drop the trailing Learn More section — its links already appear
elsewhere on the page.

https://claude.ai/code/session_019GQrc8wVq14if8f7F3pp4f

Author: claude

docs/how-it-works/oss-vs-saas.rst

@@ -25,16 +25,17 @@ The SaaS Platform is `free to get started <https://home.robusta.dev/pricing>`_,
 Open Source
 ^^^^^^^^^^^^
 
-`HolmesGPT <https://github.com/robusta-dev/holmesGPT>`_ — the SRE agent at the core of Robusta — is MIT-licensed and a CNCF sandbox project. It can be used standalone via CLI or HTTP API, without the Platform UI. See `holmesgpt.dev <https://holmesgpt.dev/>`_ for standalone usage.
+`HolmesGPT <https://github.com/robusta-dev/holmesGPT>`_ — the SRE agent at the core of Robusta — is MIT-licensed and a CNCF sandbox project. Standalone HolmesGPT is CLI- and HTTP-API-only. See `holmesgpt.dev <https://holmesgpt.dev/>`_ for standalone usage.
+
+The Robusta Platform (SaaS or Self-Hosted) adds on top:
+
+- A web interface for alert triage and investigation history
+- HolmesGPT bots for Slack and Microsoft Teams
+- Automatic alert triage and grouping
 
 Robusta Classic
 ^^^^^^^^^^^^^^^^
 
 Before HolmesGPT, Robusta's open source engine focused on rule-based automation — enriching alerts with extra context (logs, pod status, resource graphs) and routing them to Slack, Teams, and other sinks using configurable playbooks. This is sometimes referred to as **Robusta Classic**.
 
 If you are running Robusta Classic, upgrading to HolmesGPT is a configuration change — no migration required.
-
-Learn More
-^^^^^^^^^^^^
-- `Pricing Plans <https://home.robusta.dev/pricing>`_ - Compare pricing options and start a free trial
-- `HolmesGPT on GitHub <https://github.com/robusta-dev/holmesGPT>`_