docs: render-pipeline SSOT section + #78 reset pointer (redo of edits that silently failed)

The architecture and ISSUES edits in the prior commit (0013819) failed silently because
they were anchored on the session-reminder's rendering of the files, not the real text.
Redone against actual content:
- architecture doc: new 'Render Pipeline (SSOT)' section — the 3-gate patchwork vs the
  unified-PView target + the one rule (compute visibility once, enforce it once).
- ISSUES #78: promoted to the render-architecture-reset target; points to the canonical
  handoff + the architecture section.

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

docs/architecture/acdream-architecture.md

@@ -311,6 +311,51 @@ The plugin API exposes them as `WorldEntitySnapshot`. GameWindow becomes thin.
 
 ---
 
+## Render Pipeline (SSOT — current state + unified-PView target)
+
+> **The per-frame render step above is STALE** (it names deleted classes
+> `TerrainRenderer` / `StaticMeshRenderer`). The modern path (Phase N.5, mandatory) is
+> `WbDrawDispatcher` (entities) + `EnvCellRenderer` (indoor cell shells) +
+> `TerrainModernRenderer` (terrain), fed by the portal-visibility stack. This section is
+> the authoritative description of how indoor/outdoor rendering is *supposed* to work and
+> where the code currently diverges. Canonical reset handoff:
+> `docs/research/2026-05-31-render-architecture-reset-handoff.md`.
+
+**The principle (retail PView).** acdream must render the world the way retail does —
+through **one** portal-visibility traversal whose output **gates every geometry type
+uniformly**. From the player's cell, walk the portal graph; each visible cell carries a
+screen-space clip region (its portal opening, recursively intersected); the **outside**
+(terrain + outdoor scenery) is reached only through **exit portals** and is clipped to
+those openings. Interior cell shells, interior statics, and the outside are **all**
+clipped to their PView region. This is why retail is **seamless by construction**. Decomp
+anchors: `PView::ConstructView` (`:433750`), `InitCell` (`:432896`), `DrawCells`
+(`:432715`), `CEnvCell::find_visible_child_cell` (`:311397`), `SmartBox::update_viewer`
+(`:92761`). Reference port acdream owns but never invokes: WB `RenderInsideOut` /
+`VisibilityManager`.
+
+**The one rule:** *compute visibility once; enforce it once, for all geometry.* Indoors,
+you see the outside **only** through portal openings (clipped); an empty outside-view
+(windowless interior) draws **no** outdoor geometry. Outdoors, the gate is "everything."
+
+**Current divergence (the patchwork — what the reset must fix).** acdream computes the
+visibility correctly (`CellVisibility.ComputeVisibility` → `PortalVisibilityBuilder.Build`,
+a `ConstructView` port → `ClipFrameAssembler`) but then **enforces it three different,
+inconsistent ways**:
+1. `TerrainModernRenderer` — gated by `TerrainClipMode {Skip|Scissor|Planes}` (the Scissor
+   fallback over-includes).
+2. `EnvCellRenderer` — gated by the per-cell clip slot (≈correct; the shells DO render —
+   proven by the `[shell]` probe, `ACDREAM_PROBE_SHELL`).
+3. `WbDrawDispatcher` — gated by `ParentCellId ∈ visibleCellIds`, **but outdoor stabs
+   (`ParentCellId==null`) bypass the gate** → outdoor scenery/terrain shows from inside
+   (issue #78).
+
+Three gates that must agree but don't → structural seams (transparent walls,
+terrain-through-floor, grey enclosure). **The reset consolidates them into the single
+PView gate** (outside content clipped to the `OutsideView` region; no `ParentCellId==null`
+bypass; no Scissor over-include). This is a **consolidation of existing machinery**
+(`PortalVisibilityBuilder` + `ClipFrame`), not a rewrite. Do NOT add a fourth special-case
+gate to mask a seam — that anti-pattern produced the patchwork.
+
 ## Roadmap Model
 
 The old R1-R8 architecture sequence was a useful early refactor sketch, but it