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>

include/util/SafeSignal.hpp

@@ -3,10 +3,10 @@
 #include <glibmm/dispatcher.h>
 #include <sigc++/signal.h>
 
+#include <cstddef>
 #include <functional>
 #include <mutex>
 #include <queue>
-#include <cstddef>
 #include <thread>
 #include <tuple>
 #include <type_traits>

include/util/sleeper_thread.hpp

@@ -72,8 +72,7 @@ class SleeperThread {
     std::unique_lock lk(mutex_);
     CancellationGuard cancel_lock;
     return condvar_.wait(lk, [this] {
-      return signal_.load(std::memory_order_relaxed) ||
-             !do_run_.load(std::memory_order_relaxed);
+      return signal_.load(std::memory_order_relaxed) || !do_run_.load(std::memory_order_relaxed);
     });
   }
 
@@ -87,8 +86,7 @@ class SleeperThread {
       wait_end = now + dur;
     }
     return condvar_.wait_until(lk, wait_end, [this] {
-      return signal_.load(std::memory_order_relaxed) ||
-             !do_run_.load(std::memory_order_relaxed);
+      return signal_.load(std::memory_order_relaxed) || !do_run_.load(std::memory_order_relaxed);
     });
   }
 
@@ -98,8 +96,7 @@ class SleeperThread {
     std::unique_lock lk(mutex_);
     CancellationGuard cancel_lock;
     return condvar_.wait_until(lk, time_point, [this] {
-      return signal_.load(std::memory_order_relaxed) ||
-             !do_run_.load(std::memory_order_relaxed);
+      return signal_.load(std::memory_order_relaxed) || !do_run_.load(std::memory_order_relaxed);
     });
   }