feat: add DD_ORG_UUID to datadog-agent-config crate

Adds the `DD_ORG_UUID` config field to the shared `datadog-agent-config`
crate to support delegated AWS authentication. When set, consumers can
use this field to auto-enable AWS credential-based auth instead of a
static API key.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: jchrostek-dd

crates/datadog-agent-config/env.rs

@@ -478,6 +478,11 @@ pub struct EnvConfig {
     /// The delay between two samples of the API Security schema collection, in seconds.
     #[serde(deserialize_with = "deserialize_optional_duration_from_seconds")]
     pub api_security_sample_delay: Option<Duration>,
+    /// @env `DD_ORG_UUID`
+    ///
+    /// The Datadog organization UUID. When set, delegated AWS auth is auto-enabled.
+    #[serde(deserialize_with = "deserialize_optional_string")]
+    pub org_uuid: Option<String>,
 }
 
 #[allow(clippy::too_many_lines)]
@@ -680,6 +685,7 @@ fn merge_config(config: &mut Config, env_config: &EnvConfig) {
     merge_option_to_value!(config, env_config, appsec_waf_timeout);
     merge_option_to_value!(config, env_config, api_security_enabled);
     merge_option_to_value!(config, env_config, api_security_sample_delay);
+    merge_string!(config, dd_org_uuid, env_config, org_uuid);
 }
 
 #[derive(Debug, PartialEq, Clone, Copy)]
@@ -880,6 +886,7 @@ mod tests {
                 "arn:aws:ssm:us-east-1:123:parameter/key",
             ),
             ("DD_APPSEC_RULES", "/opt/custom-rules.json"),
+            ("DD_ORG_UUID", "test-org-uuid"),
         ];
 
         // Programmatic guard: count `pub ` fields in the EnvConfig struct from
@@ -955,6 +962,7 @@ mod tests {
                 Some("keep".to_string());
             expected.otlp_config_metrics_summaries_mode = Some("noquantiles".to_string());
             expected.appsec_rules = Some("/opt/custom-rules.json".to_string());
+            expected.dd_org_uuid = "test-org-uuid".to_string();
 
             assert_eq!(config, expected);
             Ok(())
@@ -1282,6 +1290,7 @@ mod tests {
                 appsec_waf_timeout: Duration::from_secs(1),
                 api_security_enabled: false,
                 api_security_sample_delay: Duration::from_secs(60),
+                dd_org_uuid: String::default(),
             };
 
             assert_eq!(config, expected_config);

crates/datadog-agent-config/mod.rs

@@ -368,6 +368,8 @@ pub struct Config {
     pub appsec_waf_timeout: Duration,
     pub api_security_enabled: bool,
     pub api_security_sample_delay: Duration,
+
+    pub dd_org_uuid: String,
 }
 
 impl Default for Config {
@@ -483,6 +485,8 @@ impl Default for Config {
             appsec_waf_timeout: Duration::from_millis(5),
             api_security_enabled: true,
             api_security_sample_delay: Duration::from_secs(30),
+
+            dd_org_uuid: String::default(),
         }
     }
 }