gatekeeper invite ports to #id_bud_btn slide-out: drop the inline #id_invite_email form, add bud-invite panel for room owner during gate phase, async POST to invite_gamer w. autocomplete + symmetric buds auto-add + slide-down Brief banner — TDD

- Brief schema (billboard/0007): post FK becomes nullable + new room FK to epic.Room + KIND_GAME_INVITE enum value. to_banner_dict resolves post_url to reverse('epic:gatekeeper', room.id) when post is null and room is set.
  - epic.invite_gamer view refactor:
    • Accepts `recipient` (matches bud-panel field; legacy `invitee_email` still works for full backwards compat).
    • Resolves via apps.billboard.views._resolve_recipient (email if "@" present, else username).
    • RoomInvite stores the resolved User's email (or raw input if unregistered).
    • Auto-adds inviter ↔ recipient to each others' buds (symmetric per Phase 2 spec) when recipient is a registered User.
    • Spawns a Brief w. owner=request.user, kind=GAME_INVITE, room=room, post=null.
    • Accept: application/json → {brief, recipient_display}; otherwise redirects to gatekeeper as before.
    • Self-invite + blank recipient: 200 w. brief=null, no RoomInvite, no buds touch.
  - _gatekeeper.html: gate-invite-panel block (lines 62-71) removed.
  - new templates/apps/billboard/_partials/_bud_invite_panel.html: clone of _bud_panel.html w. data-invite-url + autocomplete from request.user.buds. JS posts to invite_gamer + Brief.showBanner. room.html includes it owner-only when not table_status and gate_status != RENEWAL_DUE.
  - room.html scripts block now loads apps/dashboard/note.js so window.Brief is defined for the slide-down banner.
  - Tests: new test_invite_gamer.py (14 ITs) covering ajax + legacy form-submit paths, recipient resolution, RoomInvite creation, Brief w. room FK + GAME_INVITE kind, symmetric buds auto-add, unregistered/self/blank silent no-op cases. New test_gatekeeper_bud_btn.py FT (9 tests) covers presence (owner-only), absence of legacy #id_invite_email, async invite flow end-to-end (RoomInvite, Brief, banner, panel close, username resolve, buds auto-add).
  - test_brief.test_brief_owner_post_required relaxed to test_brief_owner_required (post is now nullable).
  - test_room_gatekeeper.test_second_gamer_drops_token_into_open_slot updated to drive the bud-btn flow (drops the #id_invite_email/#id_invite_btn references).
  - 866 ITs (+14) + 9 gatekeeper FTs + 28 existing room-gatekeeper FTs green.

Code architected by Disco DeDisco <discodedisco@outlook.com>
Git commit message Co-Authored-By:
Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/apps/billboard/migrations/0007_brief_room_alter_brief_kind_alter_brief_post.py

@@ -0,0 +1,30 @@
+# Generated by Django 6.0 on 2026-05-09 04:45
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('billboard', '0006_alter_line_options'),
+        ('epic', '0008_blades_reversal_fickle'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='brief',
+            name='room',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='briefs', to='epic.room'),
+        ),
+        migrations.AlterField(
+            model_name='brief',
+            name='kind',
+            field=models.CharField(choices=[('note_unlock', 'Note unlock'), ('user_post', 'User post'), ('share_invite', 'Share invite'), ('game_invite', 'Game invite')], default='user_post', max_length=32),
+        ),
+        migrations.AlterField(
+            model_name='brief',
+            name='post',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='briefs', to='billboard.post'),
+        ),
+    ]