feat: add local remote address toggle (#472)

docs/superpowers/plans/2026-04-26-allow-local-remote-addr.md

@@ -0,0 +1,171 @@
+# Allow Local Remote Address Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Add a global settings toggle that allows non-admin forward rules to target local/private addresses when explicitly enabled.
+
+**Architecture:** Keep the existing remote-address safety validator as the default path for non-admin rule changes, but gate its use behind a single backend config lookup in forward create/update handlers. Surface the toggle through the existing `vite_config` settings page and prove behavior with backend contract tests first.
+
+**Tech Stack:** Go `net/http` + GORM backend, React + TypeScript frontend settings page, Go contract tests.
+
+---
+
+### Task 1: Backend Contract Coverage
+
+**Files:**
+- Modify: `go-backend/tests/contract/forward_contract_test.go`
+
+- [ ] **Step 1: Write the failing tests**
+
+Add contract tests that prove the desired behavior:
+
+```go
+t.Run("local remote address is rejected when toggle is off", func(t *testing.T) {
+	createPayload := map[string]interface{}{
+		"name":       "deny-local-remote",
+		"tunnelId":   tunnelID,
+		"remoteAddr": "127.0.0.1:8080",
+		"strategy":   "fifo",
+	}
+	createBody, _ := json.Marshal(createPayload)
+	createReq := httptest.NewRequest(http.MethodPost, "/api/v1/forward/create", bytes.NewReader(createBody))
+	createReq.Header.Set("Authorization", adminToken)
+	createReq.Header.Set("Content-Type", "application/json")
+	createRes := httptest.NewRecorder()
+	router.ServeHTTP(createRes, createReq)
+
+	var out response.R
+	_ = json.NewDecoder(createRes.Body).Decode(&out)
+	if out.Code == 0 {
+		t.Fatalf("expected local remote address to be rejected when toggle is off")
+	}
+})
+
+t.Run("local remote address is allowed when toggle is on", func(t *testing.T) {
+	if err := repo.DB().Exec(`
+		INSERT INTO vite_config(name, value, time)
+		VALUES(?, ?, ?)
+		ON CONFLICT(name) DO UPDATE SET value = excluded.value, time = excluded.time
+	`, "allow_local_remote_addr", "1", time.Now().UnixMilli()).Error; err != nil {
+		t.Fatalf("enable allow_local_remote_addr: %v", err)
+	}
+
+	createPayload := map[string]interface{}{
+		"name":       "allow-local-remote",
+		"tunnelId":   tunnelID,
+		"remoteAddr": "127.0.0.1:8080",
+		"strategy":   "fifo",
+	}
+	createBody, _ := json.Marshal(createPayload)
+	createReq := httptest.NewRequest(http.MethodPost, "/api/v1/forward/create", bytes.NewReader(createBody))
+	createReq.Header.Set("Authorization", adminToken)
+	createReq.Header.Set("Content-Type", "application/json")
+	createRes := httptest.NewRecorder()
+	router.ServeHTTP(createRes, createReq)
+	assertCode(t, createRes, 0)
+})
+```
+
+- [ ] **Step 2: Run tests to verify they fail**
+
+Run: `go test ./tests/contract/... -run 'TestForwardContracts|local remote address'`
+Expected: FAIL because backend still rejects local/private addresses unconditionally.
+
+- [ ] **Step 3: Commit**
+
+Do not commit yet; combine with Task 2 after implementation passes.
+
+### Task 2: Backend Toggle Implementation
+
+**Files:**
+- Modify: `go-backend/internal/http/handler/mutations.go`
+
+- [ ] **Step 1: Add a tiny config helper**
+
+Add a helper near other handler helpers:
+
+```go
+func (h *Handler) allowLocalRemoteAddr() bool {
+	if h == nil || h.repo == nil {
+		return false
+	}
+	cfg, err := h.repo.GetConfigByName("allow_local_remote_addr")
+	if err != nil || cfg == nil {
+		return false
+	}
+	return strings.TrimSpace(cfg.Value) == "1"
+}
+```
+
+- [ ] **Step 2: Gate create/update validation behind the helper**
+
+Replace the unconditional checks with:
+
+```go
+if !h.allowLocalRemoteAddr() {
+	if err := IsSafeRemoteAddr(remoteAddr); err != nil {
+		response.WriteJSON(w, response.Err(403, err.Error()))
+		return
+	}
+}
+```
+
+- [ ] **Step 3: Run contract tests to verify they pass**
+
+Run: `go test ./tests/contract/... -run 'TestForwardContracts|local remote address'`
+Expected: PASS
+
+- [ ] **Step 4: Run full backend tests**
+
+Run: `go test ./...`
+Expected: PASS
+
+### Task 3: Settings Page Toggle
+
+**Files:**
+- Modify: `vite-frontend/src/pages/config.tsx`
+
+- [ ] **Step 1: Add the config item to the settings schema**
+
+Add a switch-style item for `allow_local_remote_addr` with warning copy about reduced safety.
+
+- [ ] **Step 2: Ensure the key is included in config loading/saving paths**
+
+Add `allow_local_remote_addr` anywhere the page enumerates config keys or groups persisted config values.
+
+- [ ] **Step 3: Run frontend build**
+
+Run: `pnpm run build`
+Expected: PASS
+
+- [ ] **Step 4: Run frontend lint**
+
+Run: `pnpm run lint`
+Expected: 0 errors; existing warnings may remain.
+
+### Task 4: Final Verification
+
+**Files:**
+- Verify only
+
+- [ ] **Step 1: Re-run backend contracts for the toggle**
+
+Run: `go test ./tests/contract/... -run 'TestForwardContracts|local remote address'`
+Expected: PASS
+
+- [ ] **Step 2: Re-run full backend tests**
+
+Run: `go test ./...`
+Expected: PASS
+
+- [ ] **Step 3: Re-run frontend build/lint**
+
+Run: `pnpm run build && pnpm run lint`
+Expected: Build passes, lint has no errors.
+
+- [ ] **Step 4: Commit**
+
+```bash
+git add go-backend/internal/http/handler/mutations.go go-backend/tests/contract/forward_contract_test.go vite-frontend/src/pages/config.tsx docs/superpowers/specs/2026-04-26-allow-local-remote-addr-design.md docs/superpowers/plans/2026-04-26-allow-local-remote-addr.md
+git commit -m "feat: add allow-local-remote-address toggle"
+```