t66: app names on a device that exposes none

The reported Shield names no app: `pm dump com.netflix.ninja` is ~2241 lines of
dumpsys and grep for `application-label` over the whole capture finds nothing.
The probe shipped `| head -300`, which cut the dump BEFORE the package section,
so "no label" was a truncation artefact; the sweep then named every app after
its own package id, and the apps editor pre-filled the `pkg=pkg` row the user
read as a bug.

  * the probe greps ON THE DEVICE for the three shapes Android prints
    (`application-label`, `nonLocalizedLabel`, `labelRes`); a quoted value is a
    name, `null` and a resource id are not. The dump is never truncated.
  * after APP_LABEL_PROBE_LIMIT consecutive "ran, no label" answers the device
    is taken at its word: the sweep stops spending a shell per package
    (APP_LABEL_TTL expiry re-checks, and a package whose probe FAILED still owes
    its retry — t57 UNIT 0 survives, driven by the app on screen).
  * ONE precedence chain in `ha_adb_common/app_label.resolve_package_name`, used
    by the media player, the Current App sensor, the discovery table, the source
    list and the apps editor: user map > device label > curated map > package id
    (the id shown ONCE, `name` empty when nothing names the app).
  * the curated table covers the user's 21 apps (community-maintained, not
    device truth) and the Configure row says when the device named nothing.
  * the real device shape is a test fixture (trimmed, and marked as such in the
    file: the raw capture is not in the repo) pinning that no label is
    extracted, that the probe count is bounded, and that `Netflix` surfaces.

Also drops the dead `ATTR_MEDIA_DAG_NOW_PLAYING` re-exports left by the t65
flattening and updates the RESEARCH_SHIELD now-playing note to the flat names.

No real Shield was available: the fetch/burst behaviour is exercised against the
documented Android output and the trimmed reproduction of the reported capture.

tests/test_connection.py

@@ -18,7 +18,7 @@ from nsh.connection import (
     ShieldConnectionManager,
     StateStore,
 )
-from nsh.const import ADB_POLL_INTERVAL, APP_LABEL_EXIT_MARKER
+from nsh.const import ADB_POLL_INTERVAL, APP_LABEL_EXIT_MARKER, APP_LABEL_GREP_SHAPES
 
 
 def test_connection_module_depends_on_no_homeassistant():
@@ -310,12 +310,16 @@ class TestAppLabelCache:
 
         await asyncio.sleep(0)  # drain the fetch task
 
-        # t57: the dump carries the exit marker too, so a blank answer can be
-        # told from a FAILED fetch; the package is still quoted
+        # t57: the probe carries the exit marker too, so a blank answer can be told
+        # from a FAILED fetch; the package is still quoted. t66: the label candidates
+        # are filtered ON THE DEVICE, and the 2241-line dump is never truncated —
+        # `head -300` cut it before the package section on the user's Shield.
         assert manager._poller.shell_calls == [
-            f"pm dump {shlex.quote(wicked)} 2>/dev/null | head -300; "
+            f"pm dump {shlex.quote(wicked)} 2>/dev/null | "
+            f"grep -E {shlex.quote(APP_LABEL_GREP_SHAPES)} | head -40; "
             f"echo {APP_LABEL_EXIT_MARKER}$?"
         ]
+        assert "head -300" not in manager._poller.shell_calls[0]
 
 
 class TestLogcatStream: