Refactor to support multiple instances inside single opencode process (#2360)

This release has a bunch of minor breaking changes if you are using opencode plugins or sdk

1. storage events have been removed (we might bring this back but had some issues)
2. concept of `app` is gone - there is a new concept called `project` and endpoints to list projects and get the current project
3. plugin receives `directory` which is cwd and `worktree` which is where the root of the project is if it's a git repo
4. the session.chat function has been renamed to session.prompt in sdk. it no longer requires model to be passed in (model is now an object)
5. every endpoint takes an optional `directory` parameter to operate as though opencode is running in that directory

packages/opencode/src/project/state.ts

@@ -0,0 +1,34 @@
+export namespace State {
+  interface Entry {
+    state: any
+    dispose?: (state: any) => Promise<void>
+  }
+
+  const entries = new Map<string, Map<any, Entry>>()
+
+  export function create<S>(root: () => string, init: () => S, dispose?: (state: Awaited<S>) => Promise<void>) {
+    return () => {
+      const key = root()
+      let collection = entries.get(key)
+      if (!collection) {
+        collection = new Map<string, Entry>()
+        entries.set(key, collection)
+      }
+      const exists = collection.get(init)
+      if (exists) return exists.state as S
+      const state = init()
+      collection.set(init, {
+        state,
+        dispose,
+      })
+      return state
+    }
+  }
+
+  export async function dispose(key: string) {
+    for (const [_, entry] of entries.get(key)?.entries() ?? []) {
+      if (!entry.dispose) continue
+      await entry.dispose(await entry.state)
+    }
+  }
+}