Fix: Wire OAuth config to extractors via set_oauth method

- Add set_oauth() method to Extractor trait (base.rs)
- Implement set_oauth() in PixivExtractor (pixiv.rs)
- Implement set_oauth() in DeviantArtExtractor (deviantart.rs)
- Wire OAuth config to extractors in main.rs (was placeholder)

This fixes the gap found during Phase 6 verification where OAuth
tokens from config were loaded but never passed to extractors.

src/extractor/base.rs

@@ -7,6 +7,7 @@ use regex::Regex;
 use std::collections::HashMap;
 use thiserror::Error;
 
+use crate::config::OauthConfig;
 use crate::extractor::message::Message;
 use crate::extractor::http::HttpClientError;
 
@@ -124,7 +125,14 @@ pub trait Extractor: Send + Sync {
     /// Default implementation does nothing (extractors that don't need
     /// cookies will simply ignore them).
     fn set_cookies(&mut self, _cookies: HashMap<String, String>) {}
-    
+
+    /// Set OAuth credentials for the extractor
+    ///
+    /// Called before extraction to provide OAuth authentication tokens.
+    /// Extractors that support OAuth can override this method.
+    /// Default implementation does nothing.
+    fn set_oauth(&mut self, _oauth: OauthConfig) {}
+
     /// Create a clone of this extractor
     ///
     /// This is used by the registry to create new instances

src/extractor/extractors/deviantart.rs

@@ -6,6 +6,7 @@
 use async_trait::async_trait;
 use regex::Regex;
 
+use crate::config::OauthConfig;
 use crate::extractor::{
     Extractor, ExtractorError, ExtractorMatch, Message,
 };
@@ -365,6 +366,14 @@ impl Extractor for DeviantArtExtractor {
         Box::new(self.clone())
     }
 
+    /// Set OAuth credentials for the extractor
+    fn set_oauth(&mut self, oauth: OauthConfig) {
+        self.access_token = oauth.access_token;
+        self.refresh_token = oauth.refresh_token;
+        self.client_id = oauth.client_id;
+        self.client_secret = oauth.client_secret;
+    }
+
     /// Initialize the extractor with a matched URL
     async fn initialize(&mut self, m: ExtractorMatch) -> Result<(), ExtractorError> {
         self.parse_url(&m.url)?;

src/extractor/extractors/pixiv.rs

@@ -6,6 +6,7 @@
 use async_trait::async_trait;
 use regex::Regex;
 
+use crate::config::OauthConfig;
 use crate::extractor::{
     Extractor, ExtractorError, ExtractorMatch, Message,
 };
@@ -367,6 +368,14 @@ impl Extractor for PixivExtractor {
         Box::new(self.clone())
     }
 
+    /// Set OAuth credentials for the extractor
+    fn set_oauth(&mut self, oauth: OauthConfig) {
+        self.access_token = oauth.access_token;
+        self.refresh_token = oauth.refresh_token;
+        self.client_id = oauth.client_id;
+        self.client_secret = oauth.client_secret;
+    }
+
     /// Initialize the extractor with a matched URL
     async fn initialize(&mut self, m: ExtractorMatch) -> Result<(), ExtractorError> {
         self.parse_url(&m.url)?;

src/main.rs

@@ -168,18 +168,12 @@ fn main() {
                 // Pass OAuth config to extractors that support it
                 // Check for Pixiv OAuth config
                 if let Some(oauth_config) = config.extractor.oauth.get("pixiv") {
-                    if let Some(ref access_token) = oauth_config.access_token {
-                        log::debug!("Using Pixiv OAuth access token");
-                        // Note: The extractor needs to have a method to receive OAuth tokens
-                        // This is a placeholder - actual implementation depends on extractor design
-                    }
+                    extractor.set_oauth(oauth_config.clone());
                 }
                 
                 // Check for DeviantArt OAuth config
                 if let Some(oauth_config) = config.extractor.oauth.get("deviantart") {
-                    if let Some(ref access_token) = oauth_config.access_token {
-                        log::debug!("Using DeviantArt OAuth access token");
-                    }
+                    extractor.set_oauth(oauth_config.clone());
                 }
                 
                 // Extract items using a blocking call