feat: add the community-funded Homarr assistant provider (#6563)

* Add Homarr provider proxy foundation

* Complete Homarr provider integration

* Harden Homarr provider integration

* Address Homarr provider review feedback

* Address CodeRabbit provider feedback

* Localize provider errors

* Handle provider activity load failures

* docs: improve workshop and homepage

* Harden Homarr provider limits

* fix: harden the Homarr provider

* fix: address provider review feedback

* fix: clarify provider request accounting

* feat: complete the Homarr provider endpoint

* fix: terminate invalid provider streams

packages/db/schema/postgresql.ts

@@ -486,6 +486,7 @@ export const assistantConfigurations = pgTable("assistant_configuration", {
   webSearchEnabled: boolean().notNull().default(false),
   provider: varchar({ length: 32 })
     .$type<
+      | "homarr"
       | "openrouter"
       | "openai"
       | "anthropic"