fix(config_flow): F1 — a discoverable later pairing path (Reconfigure) and truthful skip copy (t35 F1/F1b)

"Continue without protocol pairing" switched the transport off for good: the
options flow carries no protocol fields, so nothing in the UI could ever turn
it back on, and the skip copy promised nothing about it (t34 F1). The entry now
answers Home Assistant's Reconfigure action:

* async_step_reconfigure (audit G5) seeds the flow from the entry (title, adb
  host/port/enabled, androidtv entity for the host fallback) and re-runs the
  pairing step — the address is editable, the Shield shows a PIN, and
  _finish_reconfigure persists protocol_enabled=True plus the address that just
  paired (so the transport no longer depends on the ADB fallback), adopts the
  paired MAC when it differs, and updates + reloads the entry. HA derives the
  "reconfigure_successful" abort from the flow source. A Reconfigure visit that
  clicks skip aborts honestly with "reconfigure_skipped" (entry untouched), and
  an entry that is gone aborts with "reconfigure_entry_missing".
* the skip data_description now states the truth — the transport stays off
  until you pair it — and names the later path (the integration's entry menu >
  Reconfigure).
* a host corrected on the pairing form now DROPS the session started against the
  old address and restarts pairing there, so the typed address is authoritative
  instead of being paired against the stale one.
* the success path no longer runs _abort_if_unique_id_configured for a flow
  that already owns an entry: core looks the domain up by unique_id, so
  re-pairing an entry aborted on itself as "already_configured" (this also
  unblocked reauth). The fresh-setup path is unchanged.
* adjacent fix while wiring the same call: _finish_reauth passed
  `options_updates`, which core's async_update_reload_and_abort does not accept
  (the kwarg is `options`, REPLACE) — the reauth path would have raised
  TypeError in production. Both paths now pass `options` and the test stubs
  mirror the real signature.

Tests: tests/test_config_flow_ux.py::TestProtocolReconfigure drives reconfigure
from a protocol-disabled entry through to updated options (transport on, host
persisted, other options kept, MAC adopted, reload recorded), a corrected host
reopening the PIN step against the new address, the skip abort, and the
missing-entry abort; TestCopyContract gained the F1b copy pin. Against HEAD's
config_flow.py all four reconfigure tests fail (no async_step_reconfigure).

Verified: uvx --with pytest-asyncio pytest tests -q → 281 passed, 1 skipped;
uvx --with pytest-asyncio --with androidtvremote2 pytest tests -q → 282 passed;
uvx ruff check custom_components tests → clean.

custom_components/nvidia_shield/translations/en.json

@@ -57,7 +57,7 @@
         "data_description": {
           "pairing_code": "The code the Shield displays while this step is open.",
           "protocol_host": "The Shield's IP address. Pre-filled when the Shield was discovered \u2014 change it if the Shield moved.",
-          "skip_pairing": "Finishes setup now without the remote-protocol transport. Power, availability and the app push then come from the other state sources only."
+          "skip_pairing": "Finishes setup with the remote protocol off \u2014 it stays off until you pair it. Pair later from this integration's entry menu: choose Reconfigure."
         }
       },
       "reauth_confirm": {
@@ -80,6 +80,8 @@
       "reauth_successful": "Re-paired successfully.",
       "reauth_skipped": "Pairing skipped. The saved certificate is still not trusted, so the remote protocol stays unavailable until you pair again.",
       "reauth_entry_missing": "This entry no longer exists.",
+      "reconfigure_skipped": "Nothing changed \u2014 the remote protocol stays off until you pair it. Choose Reconfigure from this integration's entry menu when you are ready.",
+      "reconfigure_entry_missing": "This entry no longer exists, so there is nothing to reconfigure.",
       "zeroconf_no_host": "The discovery event carried no usable address.",
       "yaml_seed_only": {},
       "yaml_seed": {