Improve movement flow layout/animation and fix Byzantine hall doors, styles, and preload.

Co-authored-by: Cursor <cursoragent@cursor.com>

Documentation/basics.md

@@ -246,8 +246,9 @@ Each visible movement is drawn as a **portrait-width curved stream** (~54 px str
 | Feature | Implementation |
 |---------|----------------|
 | Lineage layout | `client/src/data/movement-lineage.ts` — curated predecessor→successor pairs (Met / ArtStory / museum essays); multiple parents allowed |
-| Vertical lanes | Movements whose time spans do **not** overlap (in the current zoom) share a horizontal lane; only concurrent spans stack into extra rows (`assignTemporalLanes`). A follow-up pass (`refineLanesForLineageCorridors`) pulls linked parent/child movements onto nearby or shared lanes when years allow, then displaces unrelated streams out of thick lineage branch corridors |
-| Branch connectors | Smooth curves from fan-out points along a parent stream to the **left edge (start)** of each child stream; color gradients from parent → child at constant opacity; a stream-shaped mask hides branch ink under movements so translucent overlaps do not brighten the bands |
+| Vertical lanes | Movements share a horizontal lane only when one ends at least **10 years** before the next starts (in the current zoom); closer or overlapping spans stack into extra rows (`assignTemporalLanes`). A follow-up pass (`refineLanesForLineageCorridors`) pulls linked parent/child movements onto nearby or shared lanes when years allow, then displaces unrelated streams out of thick lineage branch corridors |
+| Branch connectors | Smooth curves from fan-out points along a parent stream to the **left edge (start)** of each child stream; origin X is always strictly left of the target (time-forward only — never right→left); stroke thickness matches the **target** (child) band height; color gradients from parent → child at constant opacity; a stream-shaped mask hides branch ink under movements so translucent overlaps do not brighten the bands; pan/zoom layout changes **animate** (streams + branches chase new geometry) so shifts stay trackable |
+| Band thickness | Stream height is **proportional to `influence_link_count`** (edges on paintings by artists in that movement): thicker bands for denser influence graphs; lane rows share vertical space weighted by the thickest band in each lane |
 | Filtering | A movement is drawn when its **span overlaps** the visible year range **and** it has at least one catalogued artist — artists whose lifespan falls outside the window still keep their movement visible (their portraits simply do not render). Filtered client-side after initial load |
 | Viewport layout | Row height and stream width scale from measured canvas size so every visible movement row fits in the remaining screen space |
 
@@ -330,16 +331,16 @@ Enter from the home page by clicking a **movement name** on the movement flow (`
 |------|----------------|
 | One gallery per movement | All paintings by artists in that movement, sorted chronologically |
 | Wings | Catalog split into wings of up to **55 works** (`movementHallLayout.ts`); large movements (e.g. Baroque) use multiple wings |
-| Paintings on walls | **Left, end, and right** — end-wall works sit on the panels beside the exit doors; front wall remains passage / solid |
+| Paintings on walls | **Left, end, and right** — single-wing halls keep the far wall solid (full span); multi-wing halls hang end-wall works on panels beside the back exit |
 | Wall order | Same U-shaped hang as artist halls (left → end → right) |
 | Frame captions | **Year · artist** label below each frame |
-| Period interior | Each of the 26 seeded movements maps to a unique style in `movement-interior-styles.ts` (Italian palazzo, Baroque palace, NYC loft, white cube, etc.) |
+| Period interior | Each of the 26 seeded movements maps to a unique style in `movement-interior-styles.ts` (Italian palazzo, Baroque palace, NYC loft, white cube, etc.). Style keys use a legacy id map (`DB_ID_TO_STYLE_KEY`: gallery ids **1–26** → authored keys **27–52**, with Northern/High Renaissance swapped) so Byzantine gets the chapel, not Gothic stone |
 | Wall materials | Hi-res **procedural textures** with normal maps (`galleryProceduralTextures.ts`): real-world stone, marble, wood panelling, brick, velvet, stucco — plus **single-colour painted walls** (`painted-lime`, `painted-oil-matte`, `painted-oil-satin`, `painted-emulsion`, `painted-flat`) tinted per movement for Renaissance salons through modern white cubes |
 | Textures | Wall/floor/ceiling maps applied via `useTexturedMaterial`; movement **tints** drive painted-wall hue |
 | Windows | **Side walls only** — placed in gaps between frames (high on the wall, no overlap with paintings); style matches the movement era |
 | Lighting | Daylight from windows + ceiling track lights + ambient/sun fill |
-| Back wall | **Exit double doors** → **Wing navigator** (jump to any wing) or **Exit to Timeline** |
-| Front wall | Open **“Next wing →”** archway when a later wing exists; walk through or press `E` when near |
+| Back wall | Single wing: solid display wall. Multi-wing: **Exit double doors** → **Wing navigator** or **Exit to Timeline** |
+| Front / entrance wall | Single wing: **Exit double doors** (leave the way you entered). Multi-wing: **“Next wing →”** archway when a later wing exists |
 | Influence lamps | Same golden upside-down lamps as artist halls when `has_influence_links` is true |
 | Missing images | Draped canvas cover in frame |
 | Detail return | **Back to Gallery** from painting detail returns to the same wing with camera preserved; **Back to Timeline** exits the hall entirely |
@@ -350,8 +351,8 @@ Enter from the home page by clicking a **movement name** on the movement flow (`
 |-------|--------|
 | Walk / turn / drag | Same as artist hall |
 | Click painting | Open detail view (returns to the same wing) |
-| Back wall / `E` / **Wings / Exit →** | Open wing navigator |
-| Front archway / `E` (when near) | Advance to the **next chronological wing** |
+| Entrance / back door / `E` / **Wings / Exit →** | Open wing navigator (or exit on single-wing halls) |
+| Front archway / `E` (when near, multi-wing) | Advance to the **next chronological wing** |
 
 Movement galleries do **not** use the predecessor/successor influence picker — that remains artist-hall only.
 
@@ -371,7 +372,7 @@ Full guide: [tours.md](tours.md).
 
 ### Shared 3D behaviour
 
-**3D images** use locally cached files only (`galleryImageUrl` in `client/src/api/client.ts`). Remote fetches are too slow for realtime WebGL textures; the client calls `POST /api/artists/:id/preload-images` automatically when entering an **artist** hall (public route — links disk files only). Movement galleries load painting lists from the API without a separate preload step. While a texture is loading, the frame shows the canvas cover instead of a white placeholder.
+**3D images** use locally cached files only (`galleryImageUrl` in `client/src/api/client.ts`). Remote fetches are too slow for realtime WebGL textures; the client calls `POST /api/artists/:id/preload-images` or `POST /api/movements/:id/preload-images` automatically when entering an **artist** or **movement** hall (public routes — link disk files and regenerate missing thumbs). While a texture is loading, the frame shows the canvas cover instead of a white placeholder.
 
 **Boot overlay** (`VirtualGallery.tsx`): the center shows **“Loading gallery…”** until the WebGL canvas is ready, HDR `Environment` has settled (or timed out / failed), and a one-shot `gl.compileAsync` warm-up finishes so entrance doors / passages (often frustum-culled at spawn) do not hitch on the first turn. Painting textures keep loading in the background (prefer thumbnails; per-image timeouts; GPU upload after decode) so large halls (50+ works) are not stuck on the overlay. Env and shader warm-up also have short timeouts. The 3D hall stays mounted while painting detail or bio overlays are open; returning remounts the canvas when the hall becomes active again.
 
@@ -429,7 +430,7 @@ Next to the toggle, **Show more** (checkbox, persisted in `localStorage`) opens
 - **Guided tours** add curator-ordered winged halls with stop text on painting detail — [tours.md](tours.md).
 - **Wall hang** is shared: first work on the left at the entrance, last on the right.
 - **Influence-based hall links** connect artists through documented painting relationships, grouped by movement at the exit.
-- **3D gallery images** use locally cached files only; slow remote fetches would break realtime rendering. The client calls `POST /api/artists/:id/preload-images` automatically when entering an **artist** hall (public route — links disk files only).
+- **3D gallery images** use locally cached files only; slow remote fetches would break realtime rendering. The client calls `POST /api/artists/:id/preload-images` or `POST /api/movements/:id/preload-images` automatically when entering an artist or movement hall (public routes — link disk files and regenerate missing thumbs).
 - **3D gallery session** stays mounted while painting detail or bio overlays are open; returning to the hall remounts the WebGL canvas when it becomes active again.
 - **3D gallery resilience:** a lost WebGL context is recovered by remounting the canvas with a fresh context (rather than showing a dark window), and the HDR environment map is isolated behind an error boundary so its failure never blanks the scene.
 - **Loading feedback:** `GalleryLoadingMarker` surfaces catalog load, portrait download, gallery entry, painting-texture / GPU warm-up, Environment settle, and context-restore states so the user always knows work is still in progress.