docs: replace httpx references with httpx2

docs/developers/architecture.md

@@ -59,7 +59,7 @@ A running RomM container hosts several cooperating processes:
 
 ## Request lifecycle
 
-Every request runs the middleware stack in order, CORS → CSRF → authentication → Valkey-backed session → context vars (aiohttp + httpx clients), before FastAPI dispatches to the endpoint. Handlers do the actual work and Pydantic schemas serialise the response.
+Every request runs the middleware stack in order, CORS → CSRF → authentication → Valkey-backed session → context vars (aiohttp + httpx2 clients), before FastAPI dispatches to the endpoint. Handlers do the actual work and Pydantic schemas serialise the response.
 
 ## Backend
 

scripts/gen_platforms.py

@@ -4,7 +4,7 @@
 
 Strategy: shell out to the upstream generator at
 `backend/utils/generate_supported_platforms.py`. That module imports the
-full romm handler stack (redis, db, httpx), so it has to run inside
+full romm handler stack (redis, db, httpx2), so it has to run inside
 romm's own uv environment, not this one.
 
 Set `ROMM_SRC` to the romm checkout root (read from .env at the repo root