Optimize web_server UrlMatch to avoid heap allocations (#9263)

esphome/components/web_server/web_server.h

@@ -40,10 +40,28 @@ namespace web_server {
 
 /// Internal helper struct that is used to parse incoming URLs
 struct UrlMatch {
-  std::string domain;  ///< The domain of the component, for example "sensor"
-  std::string id;      ///< The id of the device that's being accessed, for example "living_room_fan"
-  std::string method;  ///< The method that's being called, for example "turn_on"
+  const char *domain;  ///< Pointer to domain within URL, for example "sensor"
+  const char *id;      ///< Pointer to id within URL, for example "living_room_fan"
+  const char *method;  ///< Pointer to method within URL, for example "turn_on"
+  uint8_t domain_len;  ///< Length of domain string
+  uint8_t id_len;      ///< Length of id string
+  uint8_t method_len;  ///< Length of method string
   bool valid;          ///< Whether this match is valid
+
+  // Helper methods for string comparisons
+  bool domain_equals(const char *str) const {
+    return domain && domain_len == strlen(str) && memcmp(domain, str, domain_len) == 0;
+  }
+
+  bool id_equals(const std::string &str) const {
+    return id && id_len == str.length() && memcmp(id, str.c_str(), id_len) == 0;
+  }
+
+  bool method_equals(const char *str) const {
+    return method && method_len == strlen(str) && memcmp(method, str, method_len) == 0;
+  }
+
+  bool method_empty() const { return method_len == 0; }
 };
 
 #ifdef USE_WEBSERVER_SORTING