perf(memory): eliminate deep copies in range-based for loops and lambdas

This commit addresses memory churn caused by implicit deep copies during traversal and allocation of complex structures:

- Replaced pass-by-value 'Json::Value' in std::ranges and range-based for loops with 'const auto&' or 'const Json::Value&' in Hyprland modules, preventing large JSON tree duplications on every update.

- Fixed implicit string and pair copies in UPower and CPU Frequency loops by converting 'auto' to 'const auto&' where possible.

- Added 'std::vector::reserve' calls before 'push_back' loops in MPRIS, Niri, and CFFI modules to prevent exponential vector reallocation during initialization.

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

src/modules/mpris/mpris.cpp

@@ -109,6 +109,7 @@ Mpris::Mpris(const std::string& id, const Json::Value& config)
     player_ = config_["player"].asString();
   }
   if (config_["ignored-players"].isArray()) {
+    ignored_players_.reserve(config_["ignored-players"].size());
     for (const auto& item : config_["ignored-players"]) {
       if (item.isString()) {
         ignored_players_.push_back(item.asString());