fix: safe router navigation encoding and /users/search test coverage (#133)

Author: Copilot

backend/api/internal/tests/main_test.go

@@ -80,6 +80,7 @@ func setupTestRouter() *gin.Engine {
 	router.GET("/auth/me", handlers.RequireAuth(), handlers.GetMe)
 
 	router.GET("/users", handlers.GetUsers)
+	router.GET("/users/search", handlers.SearchUsers)
 	router.GET("/users/:username", handlers.GetUserByUsername)
 	router.GET("/users/id/:user_id", handlers.GetUserById)
 	router.POST("/users", handlers.RequireAuth(), handlers.CreateUser)

backend/api/internal/tests/user_test.go

@@ -199,4 +199,26 @@ var user_tests = []TestCase{
 		ExpectedStatus: http.StatusOK,
 		ExpectedBody:   `null`,
 	},
+
+	// search users – empty q returns empty array
+	{
+		Method:         http.MethodGet,
+		Endpoint:       "/users/search?q=",
+		ExpectedStatus: http.StatusOK,
+		ExpectedBody:   `[]`,
+	},
+	// search users – prefix match returns matching users
+	{
+		Method:         http.MethodGet,
+		Endpoint:       "/users/search?q=dev",
+		ExpectedStatus: http.StatusOK,
+		ExpectedBody:   `[{"bio":"Full-stack developer passionate about open-source projects.","creation_date":"2023-12-13T00:00:00Z","id":1,"links":["https://github.com/dev_user1","https://devuser1.com"],"picture":"https://example.com/dev_user1.jpg","settings":{"accentColor":"","backgroundRefreshEnabled":false,"compactMode":false,"refreshIntervalMs":120000,"zenMode":false},"username":"dev_user1"}]`,
+	},
+	// search users – count is capped at 20
+	{
+		Method:         http.MethodGet,
+		Endpoint:       "/users/search?q=d&count=100",
+		ExpectedStatus: http.StatusOK,
+		ExpectedBody:   `[{"bio":"Data scientist with a passion for machine learning.","creation_date":"2023-06-13T00:00:00Z","id":3,"links":["https://github.com/data_scientist3","https://datascientist3.com"],"picture":"https://example.com/data_scientist3.jpg","settings":{"accentColor":"","backgroundRefreshEnabled":false,"compactMode":false,"refreshIntervalMs":120000,"zenMode":false},"username":"data_scientist3"},{"bio":"Full-stack developer passionate about open-source projects.","creation_date":"2023-12-13T00:00:00Z","id":1,"links":["https://github.com/dev_user1","https://devuser1.com"],"picture":"https://example.com/dev_user1.jpg","settings":{"accentColor":"","backgroundRefreshEnabled":false,"compactMode":false,"refreshIntervalMs":120000,"zenMode":false},"username":"dev_user1"}]`,
+	},
 }

frontend/app/(tabs)/message.tsx

@@ -313,7 +313,7 @@ export default function MessageScreen() {
     setShowNewChatModal(false);
     setSearchQuery("");
     setSuggestions([]);
-    router.push(`/conversation/${username}`);
+    router.push({ pathname: "/conversation/[username]", params: { username } });
   };
 
   const handleNewChat = () => {
@@ -342,7 +342,7 @@ export default function MessageScreen() {
     setShowNewChatModal(false);
     setSearchQuery("");
     setSuggestions([]);
-    router.push(`/conversation/${username}`);
+    router.push({ pathname: "/conversation/[username]", params: { username } });
   };
 
   const renderSuggestion = ({