fix(shell): daemon-start and health-poll auth handling; policy panel freshness

Review follow-ups on the auth-status work:

- Both daemon-start paths classified an auth-rejected hub as "daemon
  dead" via healthy() and showed a start-failure dialog while the
  shell banner above correctly blamed the token. They now share
  daemonAnswers(): only an unreachable probe counts as down.
- An auth-rejected poll now re-reads ~/.chain/hub-auth-token and
  reconnects when the file changed, so a token fixed outside Studio
  (CLI, editor) heals the connection without a restart — previously
  the client kept the stale in-memory token forever and the banner's
  own advice could not work.
- An endpoint switch resets the failure streak, so a stale in-flight
  probe can no longer let the unreachable banner blame the new
  endpoint for the old one's misses.
- The auth-policy panel re-queries when the hub token is saved or
  cleared in the panel above (reloadTick), instead of keeping a
  stale admin-denied hint; it also renders the hub's new
  reload_required flag as a pending-reload warning (DE+EN).
- today-pipeline.md still documented ~/.fai/today after the rename;
  the FAB theme comment now states the both-themes intent.

flutter analyze clean; 71 tests green including four new ones.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/l10n/app_en.arb

@@ -853,6 +853,7 @@
   "authPolicyValidatorStatic": "Validator: static token list",
   "authPolicyValidatorJwt": "Validator: JWT (RS256) via an external identity provider",
   "authPolicyAnonymous": "No tokens configured — the hub accepts anonymous calls. Fine for local work; configure tokens in ~/.chain/config.yaml for production.",
+  "authPolicyReloadRequired": "The config file (or an environment variable) changed after loading — the hub still enforces the previous state. Use “Reload” below to apply the change.",
   "authPolicyNeedsAdmin": "This view needs a token with the admin scope. Store it above under “Hub authentication” and reload.",
   "authPolicyHubTooOld": "The connected hub does not know this view yet — it is older than Studio. Update the hub (chain update apply) and reload.",
   "authPolicyRetry": "Retry",