feat(#90): IMP-56 u1-u19 catch-up before final close (post-u20 push fix)

u1: text_overrides axis in user_overrides_io
u2: structure_overrides axis in user_overrides_io
u3: vite allowlist for new endpoints
u4: text_override_resolver
u5: Step 12 text_overrides apply in phase_z2_pipeline
u6: structure_override_resolver
u7: text_path_stamper
u8: SlideCanvas text-edit capture
u9: SlideCanvas structure-edit overlay
u10: userOverridesApi service extension
u11: designAgent types extension
u12: slidePlanUtils restore
u13: user_overrides endpoint tests
u14: user_overrides restore tests
u15: pipeline fallback tests
u16: edit-mode state + gating tests
u17: slide_base print mode CSS
u18: /api/connect endpoint (vite)
u19: /api/export endpoint (vite)

Recovery scope: 29 files (12 modified + 17 new). u20 already pushed in
9439575; this commit lands u1-u19 that were authored but not committed
before #90 was externally closed.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/phase_z2/test_slide_base_print_mode.py

@@ -0,0 +1,151 @@
+"""IMP-90 (#90) u17 — slide_base.html print-mode contract tests.
+
+Stage 2 plan contract (unit u17):
+  Step 22 user-edit + Export track. The Phase Z2 print path MUST
+  auto-expand <details> popups so the FULL raw_content (MDX 원문 무손실
+  보존) is included when the user prints / exports from the browser.
+
+  u17 introduces two coordinated surfaces in
+  ``templates/phase_z2/slide_base.html``:
+
+    1. ``@media print`` CSS block — neutralizes the on-screen-only body
+       centering / box-shadow / 280px popup card clipping so the slide
+       prints at 1280×720 with the expanded popup body in static flow.
+
+    2. ``beforeprint`` / ``afterprint`` JavaScript hook at body level —
+       toggles ``details.open`` to ``true`` before the print snapshot
+       and restores the user's prior open/closed state afterwards. Body
+       level (outside any ``<details>...</details>`` block) preserves
+       the IMP-35 u8 popup-render JS-free invariant
+       (tests/phase_z2/test_slide_base_popup_render.py
+       ``test_popup_emits_no_javascript_on_render_path``).
+
+Invariants locked here:
+  P-1: ``@media print`` block is emitted exactly once in the render.
+  P-2: ``@page`` size matches the 1280×720 slide canvas.
+  P-3: ``.slide`` box-shadow + body padding/min-height neutralized at
+       print time.
+  P-4: ``.zone__popup-summary`` hidden, popup body switches from
+       absolute to static flow with unconstrained height — the popup
+       card chrome (border / shadow / 280px max-height) is unset.
+  P-5: ``beforeprint`` + ``afterprint`` listeners are wired at body
+       level (NOT inside the per-zone details block) so the popup
+       render path stays JS-free.
+  P-6: Restore semantics — the script preserves the user's prior
+       open/closed state via a single ``dataset.imp90PrintRestore`` key
+       (no global state, no event-bus mutation).
+"""
+from __future__ import annotations
+
+import re
+
+from src.phase_z2_pipeline import render_slide
+
+
+def _layout_css() -> dict:
+    return {"areas": '"primary"', "cols": "1fr", "rows": "1fr"}
+
+
+def _zone(**overrides) -> dict:
+    base = {
+        "position": "primary",
+        "template_id": "__empty__",
+        "slot_payload": {},
+    }
+    base.update(overrides)
+    return base
+
+
+def _render() -> str:
+    return render_slide(
+        slide_title="t",
+        slide_footer=None,
+        zones_data=[_zone()],
+        layout_preset="single",
+        layout_css=_layout_css(),
+        gap_px=14,
+    )
+
+
+# ─── P-1 ─ media print block presence ───────────────────────────────
+
+
+def test_media_print_block_emitted_once():
+    html = _render()
+    matches = re.findall(r"@media\s+print\s*\{", html)
+    assert len(matches) == 1
+
+
+# ─── P-2 ─ @page size matches slide canvas ──────────────────────────
+
+
+def test_page_size_matches_slide_canvas():
+    html = _render()
+    flat = re.sub(r"\s+", " ", html)
+    assert "@page { size: 1280px 720px; margin: 0; }" in flat
+
+
+# ─── P-3 ─ standalone chrome neutralized at print ───────────────────
+
+
+def test_slide_box_shadow_neutralized_at_print():
+    html = _render()
+    flat = re.sub(r"\s+", " ", html)
+    print_block = re.search(r"@media\s+print\s*\{(.*?)\}\s*</style>", flat)
+    assert print_block is not None
+    body = print_block.group(1)
+    assert "box-shadow: none !important" in body
+    assert "padding: 0 !important" in body
+    assert "min-height: 0 !important" in body
+
+
+# ─── P-4 ─ popup body switches to static flow, summary hidden ───────
+
+
+def test_popup_card_chrome_unset_at_print():
+    html = _render()
+    flat = re.sub(r"\s+", " ", html)
+    print_block = re.search(r"@media\s+print\s*\{(.*?)\}\s*</style>", flat)
+    assert print_block is not None
+    body = print_block.group(1)
+    assert ".zone__popup-summary { display: none !important; }" in body
+    assert "position: static !important" in body
+    assert "max-height: none !important" in body
+    assert "overflow: visible !important" in body
+
+
+# ─── P-5 ─ beforeprint hook is body-level (NOT inside <details>) ────
+
+
+def test_beforeprint_and_afterprint_listeners_present():
+    html = _render()
+    assert "addEventListener('beforeprint'" in html
+    assert "addEventListener('afterprint'" in html
+
+
+def test_print_script_is_outside_any_details_block():
+    """The IMP-35 u8 popup render path is JS-free. Our print script
+    sits at body level after the slide div, so no <script> appears
+    inside a <details>...</details> popup block."""
+    html = _render(
+    )
+    # No <details> in the no-popup baseline — but the assertion still
+    # holds defensively: locate every <details>...</details> block (if
+    # any) and confirm no <script> tag appears inside.
+    for block in re.findall(r"<details[\s>].*?</details>", html, re.DOTALL):
+        assert "<script" not in block
+        assert "addEventListener" not in block
+
+
+# ─── P-6 ─ restore semantics ────────────────────────────────────────
+
+
+def test_restore_uses_single_dataset_key():
+    """Restore strategy uses one dataset key
+    (``dataset.imp90PrintRestore``) — no global Set/Map, no mutation
+    of any other DOM attribute. Locks the minimal-surface contract."""
+    html = _render()
+    assert "imp90PrintRestore" in html
+    # Restore branch only sets open=false when the prior state was '0'.
+    assert "imp90PrintRestore === '0'" in html
+    assert "d.open = true" in html