feat(opencode): add plan mode, reasoning effort, and status telemetry (#688)

* feat(opencode): support plan mode

* feat(opencode): support reasoning effort

* feat(opencode): surface context usage in web

Bridge OpenCode ACP usage updates into the existing token-count pipeline so the web status bar can show live context and cache information without a separate UI path.

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(opencode): restrict plan mode to remote, rollback reasoning effort on failure

- Block local OpenCode plan startup (tools not enforced in local path)
- Allow remote OpenCode plan only (ACP permission handler denies tools)
- Guard web /permission-mode endpoint for local OpenCode plan sessions
- Rollback session reasoning effort when OpenCode rejects set_config_option
- Wire rollback callback through opencodeLoop to runOpencode closure
- Add tests: local plan rejected, remote plan allowed, web guard, effort rollback

* fix(web): auto-retry OpenCode models query to populate model selector without refresh

- Retry early failures (RPC may still be registering on new sessions)
- Poll briefly until availableModels is non-empty
- Stop polling once model options are discovered
- Add tests for retry/poll/stop policy

* fix(opencode): cap model discovery polling

---------

Co-authored-by: Cursor <cursoragent@cursor.com>

cli/src/opencode/loop.ts

@@ -18,10 +18,12 @@ interface OpencodeLoopOptions {
     api: ApiClient;
     permissionMode?: PermissionMode;
     model?: string;
+    modelReasoningEffort?: string | null;
     resumeSessionId?: string;
     hookServer: OpencodeHookServer;
     hookUrl: string;
     onSessionReady?: (session: OpencodeSession) => void;
+    onReasoningEffortRollback?: (effort: string | null) => void;
 }
 
 export async function opencodeLoop(opts: OpencodeLoopOptions): Promise<void> {
@@ -40,7 +42,8 @@ export async function opencodeLoop(opts: OpencodeLoopOptions): Promise<void> {
         mode: startingMode,
         startedBy,
         startingMode,
-        permissionMode: opts.permissionMode ?? 'default'
+        permissionMode: opts.permissionMode ?? 'default',
+        modelReasoningEffort: opts.modelReasoningEffort
     });
 
     if (opts.resumeSessionId) {
@@ -55,7 +58,9 @@ export async function opencodeLoop(opts: OpencodeLoopOptions): Promise<void> {
             hookServer: opts.hookServer,
             hookUrl: opts.hookUrl
         }),
-        runRemote: (instance) => opencodeRemoteLauncher(instance),
+        runRemote: (instance) => opencodeRemoteLauncher(instance, {
+            onReasoningEffortRollback: opts.onReasoningEffortRollback
+        }),
         onSessionReady: opts.onSessionReady
     });
 }