fix(skills): handle Windows path separator in installed status matching (#868)

* fix(skills): handle Windows path separator in installed status matching

Use regex to split directory path by both / and \ to correctly extract
the install name on Windows, fixing the issue where installed skills
were not showing as installed in the discovery page filter.

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

* feat(skills): add repository filter to skills discovery page

- Add dropdown to filter skills by repository (owner/name)
- Extract unique repos from discoverable skills list
- Add truncate style for long repo names with hover title
- Add i18n translations for zh/en/ja

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

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

src/i18n/locales/en.json

@@ -1099,7 +1099,9 @@
       "placeholder": "Filter by status",
       "all": "All",
       "installed": "Installed",
-      "uninstalled": "Not installed"
+      "uninstalled": "Not installed",
+      "repo": "Filter by repo",
+      "allRepos": "All repos"
     },
     "noResults": "No matching skills found",
     "noInstalled": "No skills installed",

src/i18n/locales/ja.json

@@ -1097,7 +1097,9 @@
       "placeholder": "状態で絞り込み",
       "all": "すべて",
       "installed": "インストール済み",
-      "uninstalled": "未インストール"
+      "uninstalled": "未インストール",
+      "repo": "リポジトリで絞り込み",
+      "allRepos": "すべてのリポジトリ"
     },
     "noResults": "一致するスキルが見つかりませんでした",
     "noInstalled": "インストールされたスキルがありません",

src/i18n/locales/zh.json

@@ -1099,7 +1099,9 @@
       "placeholder": "状态筛选",
       "all": "全部",
       "installed": "已安装",
-      "uninstalled": "未安装"
+      "uninstalled": "未安装",
+      "repo": "仓库筛选",
+      "allRepos": "全部仓库"
     },
     "noResults": "未找到匹配的技能",
     "noInstalled": "暂无已安装的技能",