Add overrides.env support for per-location service env overrides

source/src/utils/service_env_overrides.cpp

@@ -0,0 +1,51 @@
+#include "service_env_overrides.hpp"
+#include "directories.hpp"
+#include "envmanager.hpp"
+#include "service_env_validator.hpp"
+
+#include <filesystem>
+
+namespace dropshell {
+
+std::vector<OverrideChange> apply_overrides(
+    const std::string& server_name,
+    const std::string& service_name)
+{
+    std::vector<OverrideChange> changes;
+
+    std::string overrides_path = localfile::overrides_env_for_server(server_name);
+    if (overrides_path.empty() || !std::filesystem::exists(overrides_path))
+        return changes;
+
+    std::string service_env_path = localfile::service_env(server_name, service_name);
+    if (service_env_path.empty() || !std::filesystem::exists(service_env_path))
+        return changes;
+
+    // Load overrides
+    envmanager overrides(overrides_path);
+    if (!overrides.load())
+        return changes;
+
+    ordered_env_vars override_vars;
+    overrides.get_all_variables(override_vars);
+    if (override_vars.empty())
+        return changes;
+
+    // Load current service env
+    envmanager service_env(service_env_path);
+    if (!service_env.load())
+        return changes;
+
+    // Apply each override
+    for (const auto& [key, new_val] : override_vars) {
+        std::string current_val = service_env.get_variable(key);
+        if (current_val != new_val) {
+            set_env_variable(service_env_path, key, new_val);
+            changes.push_back({key, current_val, new_val});
+        }
+    }
+
+    return changes;
+}
+
+} // namespace dropshell