fix(staged): improve badge validation UX and show unique name conflicts

apps/staged/src-tauri/src/lib.rs

@@ -983,6 +983,26 @@ fn update_repo_badge(
         return Err("Hue must be between 0 and 360".into());
     }
     let store = get_store(&store)?;
+
+    // Check if another badge already uses this short name.
+    if let Some(existing) = store
+        .get_repo_badge_by_short_name(&short_name)
+        .map_err(|e| e.to_string())?
+    {
+        let is_same_badge = existing.github_repo == github_repo && existing.subpath == subpath;
+        if !is_same_badge {
+            let owner = if existing.subpath.is_empty() {
+                existing.github_repo.clone()
+            } else {
+                format!("{} ({})", existing.github_repo, existing.subpath)
+            };
+            return Err(format!(
+                "Short name '{}' is already used by {}",
+                short_name, owner
+            ));
+        }
+    }
+
     store
         .update_repo_badge(&github_repo, &subpath, &short_name, hue)
         .map_err(|e| e.to_string())?;

apps/staged/src-tauri/src/store/repo_badges.rs

@@ -93,6 +93,32 @@ impl Store {
         Ok(())
     }
 
+    /// Look up a single badge by its short_name.
+    pub fn get_repo_badge_by_short_name(
+        &self,
+        short_name: &str,
+    ) -> Result<Option<RepoBadge>, StoreError> {
+        use rusqlite::OptionalExtension;
+        let conn = self.conn.lock().unwrap();
+        conn.query_row(
+            "SELECT github_repo, subpath, short_name, hue, created_at
+             FROM repo_badges
+             WHERE short_name = ?1",
+            params![short_name],
+            |row| {
+                Ok(RepoBadge {
+                    github_repo: row.get(0)?,
+                    subpath: row.get(1)?,
+                    short_name: row.get(2)?,
+                    hue: row.get(3)?,
+                    created_at: row.get(4)?,
+                })
+            },
+        )
+        .optional()
+        .map_err(Into::into)
+    }
+
     /// Delete a badge by (github_repo, subpath).
     pub fn delete_repo_badge(&self, github_repo: &str, subpath: &str) -> Result<(), StoreError> {
         let conn = self.conn.lock().unwrap();