fix: get real skill count by awaiting discovery after adding repo

The previous approach computed count before discovery, so it was always 0.
Now we await refetchDiscoverable() after the mutation, then filter the
fresh skills list to get the actual count for the toast message.

Also reverts the SkillRepo.count field — keep the interface clean since
count is a transient UI concern, not a data model property.

src/components/skills/SkillsPage.tsx

@@ -164,10 +164,20 @@ export const SkillsPage = forwardRef<SkillsPageHandle, SkillsPageProps>(
     const handleAddRepo = async (repo: SkillRepo) => {
       try {
         await addRepoMutation.mutateAsync(repo);
+        // Await discovery so we can report the real count
+        const { data: freshSkills } = await refetchDiscoverable();
+        const count =
+          freshSkills?.filter(
+            (s) =>
+              s.repoOwner === repo.owner &&
+              s.repoName === repo.name &&
+              (s.repoBranch || "main") === (repo.branch || "main"),
+          ).length ?? 0;
         toast.success(
           t("skills.repo.addSuccess", {
             owner: repo.owner,
             name: repo.name,
+            count,
           }),
           { closeButton: true },
         );