fix: resolve state variable shadowing in command, plugin, and tool/registry

The cache→state rename caused inner InstanceState.get() results to
shadow the outer state handle, breaking type inference. Rename inner
bindings to `s` to match the convention used in the other files.

packages/opencode/src/command/index.ts

@@ -164,13 +164,13 @@ export namespace Command {
       const state = yield* InstanceState.make<State>((ctx) => init(ctx))
 
       const get = Effect.fn("Command.get")(function* (name: string) {
-        const state = yield* InstanceState.get(state)
-        return state.commands[name]
+        const s = yield* InstanceState.get(state)
+        return s.commands[name]
       })
 
       const list = Effect.fn("Command.list")(function* () {
-        const state = yield* InstanceState.get(state)
-        return Object.values(state.commands)
+        const s = yield* InstanceState.get(state)
+        return Object.values(s.commands)
       })
 
       return Service.of({ get, list })

packages/opencode/src/plugin/index.ts

@@ -279,8 +279,8 @@ export namespace Plugin {
         Output = Parameters<Required<Hooks>[Name]>[1],
       >(name: Name, input: Input, output: Output) {
         if (!name) return output
-        const state = yield* InstanceState.get(state)
-        for (const hook of state.hooks) {
+        const s = yield* InstanceState.get(state)
+        for (const hook of s.hooks) {
           const fn = hook[name] as any
           if (!fn) continue
           yield* Effect.promise(async () => fn(input, output))
@@ -289,8 +289,8 @@ export namespace Plugin {
       })
 
       const list = Effect.fn("Plugin.list")(function* () {
-        const state = yield* InstanceState.get(state)
-        return state.hooks
+        const s = yield* InstanceState.get(state)
+        return s.hooks
       })
 
       const init = Effect.fn("Plugin.init")(function* () {

packages/opencode/src/tool/registry.ts

@@ -139,18 +139,18 @@ export namespace ToolRegistry {
       })
 
       const register = Effect.fn("ToolRegistry.register")(function* (tool: Tool.Info) {
-        const state = yield* InstanceState.get(state)
-        const idx = state.custom.findIndex((t) => t.id === tool.id)
+        const s = yield* InstanceState.get(state)
+        const idx = s.custom.findIndex((t) => t.id === tool.id)
         if (idx >= 0) {
-          state.custom.splice(idx, 1, tool)
+          s.custom.splice(idx, 1, tool)
           return
         }
-        state.custom.push(tool)
+        s.custom.push(tool)
       })
 
       const ids = Effect.fn("ToolRegistry.ids")(function* () {
-        const state = yield* InstanceState.get(state)
-        const tools = yield* all(state.custom)
+        const s = yield* InstanceState.get(state)
+        const tools = yield* all(s.custom)
         return tools.map((t) => t.id)
       })
 
@@ -158,8 +158,8 @@ export namespace ToolRegistry {
         model: { providerID: ProviderID; modelID: ModelID },
         agent?: Agent.Info,
       ) {
-        const state = yield* InstanceState.get(state)
-        const allTools = yield* all(state.custom)
+        const s = yield* InstanceState.get(state)
+        const allTools = yield* all(s.custom)
         const filtered = allTools.filter((tool) => {
           if (tool.id === "codesearch" || tool.id === "websearch") {
             return model.providerID === ProviderID.opencode || Flag.OPENCODE_ENABLE_EXA