Remove item ID column references - items now use composite PK (guid, feed_url)

- Remove ID field from Item struct
- Remove ID field from SearchItem struct
- Update all SQL queries to not select id column
- Change MarkItemPublished to use feedURL/guid instead of id
- Update shortener to use item_guid instead of item_id
- Add migration to convert item_id to item_guid in short_urls table
- Update API endpoints to use feedUrl/guid instead of itemId

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

crawler.go

@@ -313,7 +313,7 @@ func (c *Crawler) StartPublishLoop() {
 			// Shorten URLs before publishing
 			itemToPublish := item
 			if item.Link != "" {
-				if shortURL, err := c.GetShortURLForPost(item.Link, &item.ID, item.FeedURL); err == nil {
+				if shortURL, err := c.GetShortURLForPost(item.Link, item.GUID, item.FeedURL); err == nil {
 					fmt.Printf("Publish: shortened %s -> %s\n", item.Link[:min(40, len(item.Link))], shortURL)
 					itemToPublish.Link = shortURL
 				} else {
@@ -324,13 +324,13 @@ func (c *Crawler) StartPublishLoop() {
 			// Publish the item
 			uri, err := publisher.PublishItem(session, &itemToPublish)
 			if err != nil {
-				fmt.Printf("Publish: failed item %d: %v\n", item.ID, err)
+				fmt.Printf("Publish: failed item %s: %v\n", item.GUID[:min(40, len(item.GUID))], err)
 				// Clear session cache on auth errors
 				if strings.Contains(err.Error(), "401") || strings.Contains(err.Error(), "auth") {
 					delete(sessions, account)
 				}
 			} else {
-				c.MarkItemPublished(item.ID, uri)
+				c.MarkItemPublished(item.FeedURL, item.GUID, uri)
 				fmt.Printf("Publish: %s -> %s\n", item.Title[:min(40, len(item.Title))], account)
 			}
 
@@ -453,7 +453,7 @@ func (c *Crawler) RefreshAllProfiles(publisher *Publisher, feedPassword string)
 // GetAllUnpublishedItems returns unpublished items from all approved feeds
 func (c *Crawler) GetAllUnpublishedItems(limit int) ([]Item, error) {
 	rows, err := c.db.Query(`
-		SELECT i.id, i.feed_url, i.guid, i.title, i.link, i.description, i.content,
+		SELECT i.feed_url, i.guid, i.title, i.link, i.description, i.content,
 		       i.author, i.pub_date, i.discovered_at, i.image_urls, i.tags,
 		       i.enclosure_url, i.enclosure_type, i.enclosure_length
 		FROM items i
@@ -477,7 +477,7 @@ func (c *Crawler) GetAllUnpublishedItems(limit int) ([]Item, error) {
 		var enclosureURL, enclosureType *string
 		var enclosureLength *int64
 
-		err := rows.Scan(&item.ID, &item.FeedURL, &guid, &title, &link, &description,
+		err := rows.Scan(&item.FeedURL, &guid, &title, &link, &description,
 			&content, &author, &pubDate, &discoveredAt, &imageURLsJSON, &tagsJSON,
 			&enclosureURL, &enclosureType, &enclosureLength)
 		if err != nil {