phase 8 step 3: needs-login partial-run mode + dashboard badge

CLAUDE.md

@@ -240,8 +240,12 @@ See PLAN.md → "Phase 8" for the full design. Summary:
   via `<meta refresh>` and renders a spinner row while
   `nixos-container create` + `update` + `start` is in flight.
 - **"needs login" partial-run state.** No valid session in `~/.claude/` →
-  harness binds the web UI but does NOT start the turn loop. Dashboard
-  surfaces this state per-agent.
+  harness binds the web UI but does NOT start the turn loop. The harness
+  polls the dir; as soon as a login lands it transitions into the turn loop
+  without a restart. Dashboard surfaces the state per-agent via a `needs
+  login` badge in the container list. "Valid session" today is a heuristic
+  (any regular file inside `/root/.claude/`); we may refine once the
+  filename layout claude writes is locked in.
 - **Login from the per-agent web UI.** Spawn `claude /login` with plain
   stdio pipes (no PTY initially), surface the OAuth URL from stdout on the
   page, accept the resulting code via a paste field, write it to the process