perf(memory): optimize C++ string operations to reduce heap fragmentation

- Replaced pass-by-value std::string parameters with const std::string&
or std::string_view to prevent SSO overallocations.

- Refactored static mapping functions in UPower to return
std::string_view instead of constructing std::string literals, enabling
perfect cache locality.

- Optimized string concatenation in hot loops (network IPs, inhibitor
lists, sway window marks) by using std::string::append() and
pre-reserving capacity instead of overloaded operator+ which produces
temporary heap instances.

These optimizations reduce high-frequency memory churn and overall heap
fragmentation within the main rendering loops.

Signed-off-by: Austin Horstman <khaneliman12@gmail.com>

src/modules/hyprland/workspaces.cpp

@@ -155,7 +155,8 @@ void Workspaces::extendOrphans(int workspaceId, Json::Value const& clientsJson)
   }
 }
 
-std::string Workspaces::getRewrite(std::string window_class, std::string window_title) {
+std::string Workspaces::getRewrite(const std::string& window_class,
+                                   const std::string& window_title) {
   std::string windowReprKey;
   if (windowRewriteConfigUsesTitle()) {
     windowReprKey = fmt::format("class<{}> title<{}>", window_class, window_title);