main: use dotenv to load .env

Cargo.lock

@@ -841,6 +841,12 @@ dependencies = [
  "litrs",
 ]
 
+[[package]]
+name = "dotenv"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77c90badedccf4105eca100756a0b1289e191f6fcbdadd3cee1d2f614f97da8f"
+
 [[package]]
 name = "dtoa"
 version = "1.0.11"
@@ -987,6 +993,7 @@ dependencies = [
  "chrono",
  "color-eyre",
  "crossterm",
+ "dotenv",
  "futures",
  "futures-timer",
  "hound",

Cargo.toml

@@ -10,6 +10,7 @@ better-panic = "0.3.0"
 chrono = { version = "0.4.44", features = ["serde"] }
 color-eyre = "0.6.5"
 crossterm = { version = "0.29.0", features = ["event-stream"] }
+dotenv = "0.15.0"
 futures = "0.3.32"
 futures-timer = "3.0.4"
 hound = "3.5.1"

src/main.rs

@@ -587,7 +587,9 @@ async fn main() {
         println!("Panic: {}", msg);
     }));
 
-    if option_env!("OPENAI_API_KEY").is_none() {
+    dotenv::dotenv().ok();
+
+    if std::env::var("OPENAI_API_KEY").is_err() {
         eprintln!("Error: OPENAI_API_KEY environment variable not set. The application will not function without it.");
         return;
     }