fix(bash): compose plugin PATH instead of stomping system PATH

When plugins return PATH entries via the shell.env hook, prepend them
to the existing system PATH instead of replacing it entirely. This
preserves standard paths like /usr/bin.

Author: micuintus

packages/opencode/src/tool/bash.ts

@@ -305,9 +305,15 @@ async function ask(ctx: Tool.Context, scan: Scan) {
 
 async function shellEnv(ctx: Tool.Context, cwd: string) {
   const extra = await Plugin.trigger("shell.env", { cwd, sessionID: ctx.sessionID, callID: ctx.callID }, { env: {} })
+  // Extract plugin PATH before spreading to compose rather than stomp
+  const env: Record<string, string> = { ...extra.env }
+  const paths = env.PATH ?? ""
+  delete env.PATH
   return {
     ...process.env,
-    ...extra.env,
+    ...env,
+    // Compose PATH: plugin bins prepended, system PATH preserved
+    ...(paths && { PATH: `${paths}${path.delimiter}${process.env.PATH ?? ""}` }),
   }
 }