feat: GuiPresence (chat-service presence backend, gateway route, mod module); restore TODO history

backend/chat-service/src/config.rs

@@ -0,0 +1,45 @@
+use anyhow::{Context, Result};
+
+#[derive(Clone)]
+pub struct Config {
+    pub port: u16,
+    pub internal_key: String,
+}
+
+impl Config {
+    pub fn from_env() -> Result<Config> {
+        Ok(Config {
+            port: std::env::var("CHAT_PORT")
+                .unwrap_or_else(|_| "8083".into())
+                .parse()
+                .context("CHAT_PORT")?,
+            internal_key: std::env::var("INTERNAL_KEY").context("INTERNAL_KEY not set")?,
+        })
+    }
+
+    pub fn validate(&self) -> Result<()> {
+        if self.internal_key.len() < 32 {
+            anyhow::bail!("INTERNAL_KEY must be at least 32 bytes");
+        }
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn short_key_is_rejected() {
+        let c = Config {
+            port: 0,
+            internal_key: "short".into(),
+        };
+        assert!(c.validate().is_err());
+        let c = Config {
+            port: 0,
+            internal_key: "k".repeat(32),
+        };
+        assert!(c.validate().is_ok());
+    }
+}