feat(web): inline-expand summary + Q&A in the list (ADR-031, #16)

Click a summarized card → its full summary (summaryBody) + chat dock (chatReveal)
expand in place via HTMX (GET /v/{id}/expand → expandedCard), collapse back via
GET /v/{id}/card → compact VideoCard. Same <li id>, outerHTML swap — the existing
list-fragment pattern. The card title carries href=/v/{id} as the no-JS fallback
(detail page stays for no-JS + deep links); only summarized cards expand. Reuses
summaryBody + chatReveal so the expanded card never drifts from the detail page.

BDD: inline_expand.feature un-pended + mapped. TDD: 6 handler/fragment tests
(expand/collapse fragments, chat dock, summarized-only, no-JS href, shared body).
Minimal CSS only — the TUI/charm restyle is #17.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/web/inline_expand_test.go

@@ -0,0 +1,107 @@
+package web_test
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestExpandReturnsSummaryBodyFragment: GET /v/{id}/expand returns the full
+// summary as an in-place card fragment (not a full page) — ADR-031.
+func TestExpandReturnsSummaryBodyFragment(t *testing.T) {
+	ctx := context.Background()
+	app := newApp(t)
+	p := rawPool(t)
+	resetDB(t, p)
+	require.NoError(t, deliver(ctx, app, videoX, "the full summary text"))
+	seedVideo(t, p, videoX, "X Title", "https://x", time.Time{})
+
+	html := body(t, do(t, app, httptest.NewRequest(http.MethodGet, "/v/"+videoX+"/expand", nil)))
+	require.Contains(t, html, "the full summary text")
+	require.Contains(t, html, "Takeaways")
+	require.Contains(t, html, "highlight one")
+	require.Contains(t, html, "card-expanded", "rendered as the expanded card")
+	require.Contains(t, html, "/v/"+videoX+"/card", "carries a collapse affordance")
+	require.NotContains(t, html, "<html", "fragment, not a full page")
+}
+
+// TestCollapseReturnsCompactCard: GET /v/{id}/card returns the compact card with
+// the expand affordance — the collapse target.
+func TestCollapseReturnsCompactCard(t *testing.T) {
+	ctx := context.Background()
+	app := newApp(t)
+	p := rawPool(t)
+	resetDB(t, p)
+	require.NoError(t, deliver(ctx, app, videoX, "summary text"))
+	seedVideo(t, p, videoX, "X Title", "https://x", time.Time{})
+
+	html := body(t, do(t, app, httptest.NewRequest(http.MethodGet, "/v/"+videoX+"/card", nil)))
+	require.Contains(t, html, `class="card"`, "compact card")
+	require.Contains(t, html, "/v/"+videoX+"/expand", "compact card offers expand")
+	require.NotContains(t, html, "card-expanded")
+	require.NotContains(t, html, "<html", "fragment, not a full page")
+}
+
+// TestExpandedCardOffersChatDock: with chat enabled, the expanded card includes
+// the deeper-dive chat affordance.
+func TestExpandedCardOffersChatDock(t *testing.T) {
+	ctx := context.Background()
+	app := newChatApp(t, &fakeChatter{models: []string{"m"}}, nil)
+	p := rawPool(t)
+	resetDB(t, p)
+	require.NoError(t, deliver(ctx, app, videoX, "summary text"))
+	seedVideo(t, p, videoX, "X Title", "https://x", time.Time{})
+
+	html := body(t, do(t, app, httptest.NewRequest(http.MethodGet, "/v/"+videoX+"/expand", nil)))
+	require.Contains(t, html, "/v/"+videoX+"/chat", "expanded card wires the chat dock")
+}
+
+// TestCompactCardExpandOnlyWhenSummarized: a not-yet-summarized card shows its
+// summarize footer and no expand affordance.
+func TestCompactCardExpandOnlyWhenSummarized(t *testing.T) {
+	app := newApp(t)
+	p := rawPool(t)
+	resetDB(t, p)
+	seedVideo(t, p, videoX, "Pending Title", "https://x", time.Time{}) // no summary
+
+	html := body(t, do(t, app, httptest.NewRequest(http.MethodGet, "/v/"+videoX+"/card", nil)))
+	require.Contains(t, html, "Not summarized")
+	require.NotContains(t, html, "/v/"+videoX+"/expand", "pending card offers no expand")
+}
+
+// TestCompactCardHasNoJSDetailFallback: the expand affordance carries an href to
+// the detail page, so JS-off users still reach the full summary.
+func TestCompactCardHasNoJSDetailFallback(t *testing.T) {
+	ctx := context.Background()
+	app := newApp(t)
+	p := rawPool(t)
+	resetDB(t, p)
+	require.NoError(t, deliver(ctx, app, videoX, "summary text"))
+	seedVideo(t, p, videoX, "X Title", "https://x", time.Time{})
+
+	html := body(t, do(t, app, httptest.NewRequest(http.MethodGet, "/v/"+videoX+"/card", nil)))
+	require.Contains(t, html, `href="/v/`+videoX+`"`, "no-JS fallback to the detail page")
+	require.Contains(t, html, "/v/"+videoX+"/expand", "and the HTMX expand for JS users")
+}
+
+// TestDetailAndExpandShareSummaryBody: the detail page and the expanded card render
+// the same summary body (one shared fragment, no drift).
+func TestDetailAndExpandShareSummaryBody(t *testing.T) {
+	ctx := context.Background()
+	app := newApp(t)
+	p := rawPool(t)
+	resetDB(t, p)
+	require.NoError(t, deliver(ctx, app, videoX, "shared summary text"))
+	seedVideo(t, p, videoX, "X Title", "https://x", time.Time{})
+
+	detail := body(t, do(t, app, httptest.NewRequest(http.MethodGet, "/v/"+videoX, nil)))
+	expand := body(t, do(t, app, httptest.NewRequest(http.MethodGet, "/v/"+videoX+"/expand", nil)))
+	for _, want := range []string{"shared summary text", "Takeaways", "highlight one"} {
+		require.Contains(t, detail, want)
+		require.Contains(t, expand, want)
+	}
+}