Reapply "tweak: adjust keys for uniqueness calculations to use provider/model"

This reverts commit 9d32a0354f1db3ea4893f4ad00900c6420ab78c6.

packages/opencode/src/cli/cmd/tui/context/local.tsx

@@ -253,7 +253,7 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
           const next = favorites[index]
           if (!next) return
           setModelStore("model", agent.current().name, { ...next })
-          const uniq = uniqueBy([next, ...modelStore.recent], (x) => x.providerID + x.modelID)
+          const uniq = uniqueBy([next, ...modelStore.recent], (x) => `${x.providerID}/${x.modelID}`)
           if (uniq.length > 10) uniq.pop()
           setModelStore(
             "recent",
@@ -273,7 +273,7 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
             }
             setModelStore("model", agent.current().name, model)
             if (options?.recent) {
-              const uniq = uniqueBy([model, ...modelStore.recent], (x) => x.providerID + x.modelID)
+              const uniq = uniqueBy([model, ...modelStore.recent], (x) => `${x.providerID}/${x.modelID}`)
               if (uniq.length > 10) uniq.pop()
               setModelStore(
                 "recent",