feat(spoof): periodic bulletin refresh via BulletinPoller

BulletinPoller fetches the Pixel security bulletin index page on
its own HandlerThread with 5s/30s/2m/10m/30m bootstrap backoff,
then 24h steady cadence. The first <td>YYYY-MM-DD</td> match is
the latest published patch; newer-than-current dates flow through
PatchLevelManager.updateTo for validation + atomic write + resetprop.

Persists the last 10 attempts to last_bulletin_fetch.json (atomic
rename) with status, http_code, parsed_date, applied, and error
fields so operators can audit history without logcat.

Sepolicy rule appends TCP-socket allow rules for both ksu and
magisk source domains so HttpsURLConnection survives SELinux
enforcement on either root provider. Uninstall.sh cleans the
three new artifacts.

module/sepolicy.rule

@@ -1,2 +1,9 @@
 allow keystore {adb_data_file shell_data_file} file *
 allow crash_dump keystore process *
+
+allow ksu self:tcp_socket { create connect read write getopt setopt }
+allow ksu node:tcp_socket node_bind
+allow ksu port:tcp_socket name_connect
+allow magisk self:tcp_socket { create connect read write getopt setopt }
+allow magisk node:tcp_socket node_bind
+allow magisk port:tcp_socket name_connect

module/uninstall.sh

@@ -10,3 +10,4 @@ done
 rm -rf "$CONFIG_DIR/persistent_keys"
 rm -f "$CONFIG_DIR/tee_status.txt"
 rm -f "$CONFIG_DIR/boot_hash.bin" "$CONFIG_DIR/boot_key.bin"
+rm -f "$CONFIG_DIR/security_patch.txt" "$CONFIG_DIR/security_patch.txt.next" "$CONFIG_DIR/last_bulletin_fetch.json"