Refresh JPG marketing visuals to Nexus One AI Workstation/Server structure

- Rebuild package-overview, opportunity, and tier-comparison as SVGs in the
  established dark/violet design language, exported to JPG at 1500x844.
- Fix 'Cezen AI Package' branding violation in package-overview.
- Relabel Starter/Basic/Pro/Max -> Server S/M/L/Max across all three visuals.
- Add standalone Workstation category, distinct from the Server ladder.
- Update terminology: Agent Builder & Workflows -> Agent Studio & Workflow
  Designer, Connectors -> MCP & Enterprise Connectors.
- Update docs/README.md: all core collateral is now current, no refresh
  pending.

docs/README.md

@@ -29,13 +29,10 @@ S/M/L/Max — the same four tiers as before, relabeled). See the main repo
 `README.md` → "Product Structure" and "Platform Roadmap" sections for the
 full structure and the seven planned enterprise capabilities.
 
-`Nexus_One_AI_Datasheet.docx`/`.pdf`, `architecture-overview.svg`, and
+All core collateral and visuals are current: `Nexus_One_AI_Datasheet.docx`/
-`technical-service-flow.svg` are updated to this structure — Server S/M/L/Max
+`.pdf`, `architecture-overview.svg`, `technical-service-flow.svg`, and the
-labeling throughout, a Workstation callout, and a Platform Roadmap section in
+three `.jpg` visuals below all use Server S/M/L/Max labeling and a standalone
-the datasheet. The three `.jpg` visuals below (package overview, opportunity,
+Workstation callout. No collateral currently predates the relabeling.
-tier comparison) are raster images from an earlier design pass and still
-predate this relabeling — they need a design refresh, not a text edit, and
-are tracked as follow-up work.
 
 ## Suggested Usage