infrastructure: big-picture diagram now shows all three providers with value tiers

infrastructure.md

@@ -6,16 +6,21 @@ and contributors who want to work on it.
 ## The big picture
 
 Members reach the co-op through two front doors: the **chat** (Open WebUI) and
-the **API** (the LiteLLM gateway). Both route through a single gateway to cloud
-LLM providers running inside **TEE-protected enclaves** (Tinfoil), so inference
-is private end-to-end. A thin layer of custom middleware — the member portal —
-ties Open Collective membership to Cloudron accounts and LiteLLM keys.
+the **API** (the LiteLLM gateway). Both route through a single gateway to
+multiple LLM providers — so members choose what they value for each task:
+architecturally private inference in **TEE-protected enclaves** (Tinfoil),
+100% renewable energy (GreenPT), or publicly developed sovereign models
+(PublicAI). A thin layer of custom middleware — the member portal — ties Open
+Collective membership to Cloudron accounts and LiteLLM keys.
 
 ```
-Members ──> Open WebUI (chat) ─┐
-                               ├──> LiteLLM gateway ──> Tinfoil (TEE) ──> models
-Members ──> your own tools ────┘
-                          (API)
+                                              ┌─> Tinfoil (TEE)      🔒 private
+Members ──> Open WebUI (chat) ─┐              │
+                               ├──> LiteLLM ──┼─> GreenPT (renewable) 🌱 green
+Members ──> your own tools ────┘    gateway   │
+                          (API)     (keys,    └─> PublicAI (open)     📖 public
+                                    metering,
+                                    routing)
 ```
 
 The whole stack runs on [Cloudron](https://cloudron.io), which handles hosting,