My Sign DEL btn: clear-sign affordance on SCAN SIGN landing — Sprint 4b-adjacent of My Sea roadmap — TDD

Pre-spec'd in [[sprint-my-sea-sign-gate-may19]] as the unblocker for tomorrow's visual verification of 4b's no-sig branch — admin user (@disco) had a saved sig from Sprint 4a testing & there was no in-UI affordance to undo it short of DB surgery. Lands ahead of the deferred 4b visual verify so dev users can toggle between sig/no-sig states on Claudezilla.

- Endpoint: `path("my-sign/clear", views.clear_sign, name="clear_sign")` — POST sets `User.significator = None` + `significator_reversed = False`, redirects to picker; GET is a no-mutation redirect to picker (mirrors save_sign's GET handling). `login_required(login_url="/")`. No trailing slash per [[feedback_url_convention_actions_no_trailing_slash]] (action endpoint, not page).
- Template (my_sign.html): `<form id="id_clear_sign_form" class="my-sign-clear-form">` w. `<button id="id_clear_sign_btn" class="btn btn-danger">DEL</button>`, rendered ONLY when `current_significator` is set; sits inside `.my-sign-landing` as a sibling of `.room-shell` so it's bound to the landing-phase UI alone (picker phase already has its own NVM unlock affordance on focused thumbnails).
- SCSS: anchored bottom-right of `.my-sign-landing` via `position: absolute; bottom: .75rem; right: 1rem` — `.my-sign-landing` gains `position: relative` to scope the absolute. `.btn-danger` carries the destructive treatment; "DEL" mirrors post.html gear menu's DEL convention from [[sprint-post-polish-may13]].
- 3 FTs in new `MySignClearTest` class — covers: btn renders on landing when sig saved (T1, asserts text "DEL" + `.btn-danger` class); btn absent when no sig (T2); click POSTs, reloads, & wipes `User.significator` + `significator_reversed` in DB (T3).
- 6 ITs in new `ClearSignViewTest` + `MySignClearAffordanceTemplateTest` — covers: login_required gate, POST wipes both fields w. redirect-back, GET redirects w.o mutation, POST-w/o-existing-sig is idempotent no-op, template renders btn only when sig set, template's form action targets `clear_sign` reverse.
- 1029 IT/UT green in 47s (+6 from baseline); 20/20 FT green across test_bill_my_sign + test_game_my_sea in 165s.

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

src/functional_tests/test_bill_my_sign.py

@@ -451,3 +451,91 @@ class MySignBackupDeckTest(FunctionalTest):
             href.endswith("/gameboard/"),
             f"FYI should link to /gameboard/, got {href!r}",
         )
+
+
+class MySignClearTest(FunctionalTest):
+    """Clear-sign affordance on the SCAN SIGN landing screen.
+
+    Sprint 4b-adjacent (2026-05-19): the only way to undo a saved sig was
+    DB surgery — which blocked manual verification of [[sprint-my-sea-sign-
+    gate-may19]]'s no-sig branch on dev users w. a sig already set. Design
+    pre-spec'd in the 4b memory: a small CLEAR btn on the SCAN SIGN
+    landing screen, visible only when `user.significator` is set; POST
+    clears the FK + reversed flag + reloads to the no-sig landing."""
+
+    def setUp(self):
+        super().setUp()
+        _seed_earthman_sig_pile()
+        _seed_my_sign_applet()
+        self.email = "clear@test.io"
+        self.gamer = User.objects.create(email=self.email)
+        sig_pile = personal_sig_cards(self.gamer)
+        self.target_card = sig_pile[0] if sig_pile else None
+        self.assertIsNotNone(self.target_card)
+        # Pre-save a sig so the CLEAR affordance is visible on landing.
+        self.gamer.significator = self.target_card
+        self.gamer.significator_reversed = False
+        self.gamer.save(update_fields=["significator", "significator_reversed"])
+
+    # ── Test 1 ───────────────────────────────────────────────────────────────
+
+    def test_clear_sign_btn_renders_on_landing_when_sig_saved(self):
+        """When `user.significator` is set, the landing screen shows a
+        DEL btn alongside SCAN SIGN. Uses .btn-danger for destructive
+        action treatment (mirrors post.html gear menu DEL)."""
+        self.create_pre_authenticated_session(self.email)
+        self.browser.get(self.live_server_url + "/billboard/my-sign/")
+        btn = self.wait_for(
+            lambda: self.browser.find_element(
+                By.CSS_SELECTOR, "#id_clear_sign_btn"
+            )
+        )
+        self.assertTrue(btn.is_displayed())
+        self.assertIn("DEL", btn.text.upper())
+        self.assertIn("btn-danger", btn.get_attribute("class"))
+
+    # ── Test 2 ───────────────────────────────────────────────────────────────
+
+    def test_clear_sign_btn_absent_when_no_sig_saved(self):
+        """Fresh user w. no significator → no CLEAR btn on the landing."""
+        # Wipe the sig set in setUp so this user lands in the no-sig state.
+        self.gamer.significator = None
+        self.gamer.save(update_fields=["significator"])
+        self.create_pre_authenticated_session(self.email)
+        self.browser.get(self.live_server_url + "/billboard/my-sign/")
+        # Wait for the page to settle on the SCAN SIGN btn (proxy for landing).
+        self.wait_for(
+            lambda: self.browser.find_element(By.CSS_SELECTOR, "#id_scan_sign_btn")
+        )
+        self.assertEqual(
+            len(self.browser.find_elements(
+                By.CSS_SELECTOR, "#id_clear_sign_btn"
+            )),
+            0,
+        )
+
+    # ── Test 3 ───────────────────────────────────────────────────────────────
+
+    def test_clear_sign_click_wipes_sig_and_reloads_to_no_sig_landing(self):
+        """Click CLEAR SIGN → POST → page reloads → landing shows the
+        no-sig state (no stage card preview, no CLEAR btn) + the DB has
+        `user.significator = None`."""
+        self.create_pre_authenticated_session(self.email)
+        self.browser.get(self.live_server_url + "/billboard/my-sign/")
+        btn = self.wait_for(
+            lambda: self.browser.find_element(By.CSS_SELECTOR, "#id_clear_sign_btn")
+        )
+        btn.click()
+        # After the POST → redirect → GET, the CLEAR btn should no longer
+        # exist + the stage card preview should be hidden.
+        self.wait_for(
+            lambda: self.assertEqual(
+                len(self.browser.find_elements(
+                    By.CSS_SELECTOR, "#id_clear_sign_btn"
+                )),
+                0,
+            )
+        )
+        self.gamer.refresh_from_db()
+        self.assertIsNone(self.gamer.significator)
+        self.assertFalse(self.gamer.significator_reversed)