brief sprint C3.a: Note unlock spawns Line + Brief on the user's per-category Post; banner JS consumes the new brief payload (FYI → post detail, square → my-notes) — TDD

Wires the C2 Brief model into the existing Note-unlock pipeline. Per the per-category Post model: each user has a single Post(owner=user, kind=NOTE_UNLOCK) titled by the header Line "Look! — new Note unlocked"; each unlock appends a per-event Line ("Stargazer, 5:21:00 PM") + spawns a Brief FK'd to that Line.

Server:
- billboard.Post gains a `kind` enum (NOTE_UNLOCK / USER_POST / SHARE_INVITE, default USER_POST) so the per-category Post is deterministically discoverable via (owner, kind=NOTE_UNLOCK).
- drama.Note.grant_if_new now returns (note, created, brief) — backwards-incompat tuple shape; the new third slot is None on idempotent re-grants. On a fresh grant it: get-or-creates the user's Note Unlocks Post; ensures the header Line; appends a per-event Line w. timestamp; creates a Brief(kind=NOTE_UNLOCK, owner, post, line, title=note.display_title).
- dashboard.views.sky_save's response shape flips {note: {...}|null} → {brief: {...}|null}. The new helper _brief_to_banner_dict exposes {id, kind, title, line_text, post_url, square_url, created_at}; for NOTE_UNLOCK kind, square_url = reverse('billboard:my_notes').

Banner JS (apps/dashboard/note.js):
- Module renamed Note → Brief (Note kept as an alias during the C3 sprint; will retire in C3.e). showBanner now consumes the Brief shape: title from brief.title, body from brief.line_text, time from brief.created_at, FYI href = brief.post_url, NVM dismisses, .note-banner__image is rendered as a clickable <a href=brief.square_url> when square_url is set. The CSS class names (.note-banner, .note-banner__title, etc.) stay so all existing SCSS + FT selectors keep working.
- sky.html + _applet-my-sky.html flip Note.handleSaveResponse → Brief.handleSaveResponse.

Tests:
- new IT class GrantIfNewSpawnsBriefTest (5 tests): first grant creates Post+Line+Brief, idempotent on second grant returns no brief, two different slugs share one Post, line text carries note title, post.kind == NOTE_UNLOCK. PostKindFieldTest (2 tests): default user_post + all three choices present.
- existing drama test_models.GrantIfNew tests updated to unpack the third tuple element.
- dashboard.tests.integrated.test_sky_views: 5 tests flipped from data["note"] → data["brief"] w/ the new payload shape (kind=note_unlock, title=Stargazer, line_text contains Stargazer, post_url under /billboard/post/, square_url=/billboard/my-notes/).
- NoteSpec.js (Jasmine): 12 specs rewritten for the Brief shape — SAMPLE_BRIEF carries the seven fields, T6 asserts the square is a clickable <a>, T8 asserts FYI points at brief.post_url (was hardcoded /billboard/my-notes/).
- functional_tests.test_applet_my_notes: T2 split — FYI now navigates to /billboard/post/<uuid>/ (the post detail / mark-read contract), the .note-banner__image square preserves the legacy jump direct to /billboard/my-notes/.

billboard/0003_post_kind migration auto-generated. 808 ITs + 9 my_notes FTs + 1 Jasmine FT all green.

Code architected by Disco DeDisco <discodedisco@outlook.com>
Git commit message Co-Authored-By:
Claude Sonnet 4.6 <noreply@anthropic.com>

src/apps/drama/models.py

@@ -237,8 +237,41 @@ class Note(models.Model):
 
     @classmethod
     def grant_if_new(cls, user, slug):
+        """Grants the Note if it doesn't already exist on the user; on a fresh
+        grant ALSO appends a Line to the user's per-category "Note Unlocks"
+        Post (creating the Post on first-ever unlock) and spawns a Brief that
+        FKs the appended Line. Returns ``(note, created, brief)`` — brief is
+        None on idempotent re-grants. Banner-side affordances (FYI navigation,
+        my-notes square) ride on the Brief.kind=NOTE_UNLOCK discriminator."""
         from django.utils import timezone
-        return cls.objects.get_or_create(
+
+        from apps.billboard.models import Brief, Line, Post
+
+        note, created = cls.objects.get_or_create(
             user=user, slug=slug,
             defaults={"earned_at": timezone.now()},
         )
+        if not created:
+            return note, created, None
+
+        post, _ = Post.objects.get_or_create(
+            owner=user, kind=Post.KIND_NOTE_UNLOCK,
+        )
+        # Per-category header Line (becomes Post.name) — only added once on
+        # first-ever unlock for this user.
+        Line.objects.get_or_create(post=post, text="Look! — new Note unlocked")
+        # Per-event Line — text dedupe is enforced by the unique_together on
+        # (post, text), so two unlocks of the same slug at the same minute
+        # would clash; the timestamp suffix carries the second of resolution.
+        # %-I (lstrip-zero hour) is POSIX-only; %I gives "05:21:00 PM" — fine
+        # on Windows + Linux, and the leading zero is acceptable in a Line.
+        line_text = f"{note.display_title}, {note.earned_at:%I:%M:%S %p}"
+        line = Line.objects.create(post=post, text=line_text)
+        brief = Brief.objects.create(
+            owner=user,
+            post=post,
+            line=line,
+            kind=Brief.KIND_NOTE_UNLOCK,
+            title=note.display_title,
+        )
+        return note, created, brief