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+Feature: Inline-expand summary + Q&A in the list (ADR-031, #16)
+  As a reader skimming my summaries
+  I want to open a summary and its Q&A in place in the list
+  So that I get the full read and follow-up without leaving the list (SPA-like, no page hop)
+
+  # HTMX inline-expand, no SPA framework (ADR-031). Each scenario maps to a Go test
+  # in scenario_coverage_test.go; tagged @pending until the TDD step lands it.
+
+  @pending  # TestExpandReturnsSummaryBodyFragment
+  Scenario: A summarized card expands to the full summary in place
+    Given a summarized video in my list
+    When I expand its card
+    Then the full summary, highlights, and takeaways are returned as an in-place card fragment, not a full page
+
+  @pending  # TestCollapseReturnsCompactCard
+  Scenario: An expanded card collapses back to the compact card
+    Given an expanded card
+    When I collapse it
+    Then the compact card fragment is returned in its place
+
+  @pending  # TestExpandedCardOffersChatDock
+  Scenario: The expanded card offers the Q&A dock
+    Given chat is enabled
+    When a summarized card is expanded
+    Then the expanded card includes the deeper-dive chat affordance for that video
+
+  @pending  # TestCompactCardExpandOnlyWhenSummarized
+  Scenario: Only a summarized card offers expand
+    Given a discovered but not-yet-summarized card
+    When the card is rendered
+    Then it shows its summarize/queue footer and no expand affordance
+
+  @pending  # TestCompactCardHasNoJSDetailFallback
+  Scenario: With JS off the card still reaches the full summary
+    Given a summarized card
+    When it is rendered
+    Then its expand affordance carries an href to the detail page as a no-JS fallback
+
+  @pending  # TestDetailAndExpandShareSummaryBody
+  Scenario: The detail page and the expanded card show the same summary
+    Given a summarized video
+    When I view it on the detail page and as an expanded card
+    Then both render the same summary body (one shared fragment, no drift)