feat(ui): E31 S4a — rail rows are links, the channel page opens on unwatched, users and audit tidied

- Nav rail page rows are real links (/?page=<id>): a middle-click or
  Ctrl-click opens the page in a new tab; a plain click stays in-app.
- A fresh channel page shows the unwatched videos; a picked watch state
  is a remembered preference (channelShow).
- Users: the role, suspend and delete move into the row's one menu
  (the "…", right-click, Shift+F10); locked ones keep their reason.
- Audit log: back-to-back successful runs of one job fold into one row
  that opens to the earlier ones; a failed run reads in the danger colour.
- DESIGN.md decision log: the E31 picks.

frontend/src/i18n/locales/en/audit.json

@@ -19,5 +19,7 @@
     "actor": "Who",
     "action": "Action",
     "details": "Details"
-  }
+  },
+  "earlierRuns_one": "{{count}} earlier run",
+  "earlierRuns_other": "{{count}} earlier runs"
 }

frontend/src/i18n/locales/en/users.json

@@ -101,5 +101,6 @@
     "setPassword": "Create a set-password link",
     "setPasswordAgain": "Create another link",
     "linkFailed": "Couldn't create the link. Please try again."
-  }
+  },
+  "rowMenu": "User actions"
 }

frontend/src/i18n/locales/hu/audit.json

@@ -19,5 +19,7 @@
     "actor": "Ki",
     "action": "Művelet",
     "details": "Részletek"
-  }
+  },
+  "earlierRuns_one": "{{count}} korábbi futás",
+  "earlierRuns_other": "{{count}} korábbi futás"
 }

frontend/src/i18n/locales/hu/users.json

@@ -101,5 +101,6 @@
     "setPassword": "Jelszóbeállító link készítése",
     "setPasswordAgain": "Új link készítése",
     "linkFailed": "Nem sikerült létrehozni a linket. Próbáld újra."
-  }
+  },
+  "rowMenu": "Felhasználó műveletei"
 }