Add vertical bottom-up timeline with center-out streams and smooth layout transitions.

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

Documentation/basics.md

@@ -6,8 +6,8 @@ Interactive virtual museum spanning art history: zoomable timeline with event gu
 
 The app is organised as a **drill-down hierarchy**:
 
-1. **Timeline** — historical eras (Ancient → Contemporary) with definite or fuzzy date boundaries.
-2. **Movement flow** — art movements as curved SVG streams on the same year axis; documented predecessor→successor branches; portrait thumbnails placed along each stream.
+1. **Timeline** — historical eras (Ancient → Contemporary) with definite or fuzzy date boundaries; classic left→right or vertical bottom→up layout (header link).
+2. **Movement flow** — art movements as SVG streams on the same year axis; documented predecessor→successor branches (classic); portrait thumbnails along each stream.
 3. **3D gallery** — one personal hall per artist, a **movement gallery** (click a movement name → artist filter → hall), or a **guided tour** hall (timeline → **Tours**): period-themed or tour wings of up to ~55 works, U-shaped hang (left → end wall → right).
 4. **Painting detail** — full work in the centre, *Influenced By* on the left, *Influenced* on the right (paintings, artists, or movements), optional **curator notes** and **art-history notes** with image markers, prev/next catalog browsing, optional fullscreen, link to artist biography.
 5. **Artist biography** — portrait, lifespan, movement, and Wikipedia-sourced intro text (`bio_short` / `bio_full`). With debug mode on, the same image-audit panel as painting detail (portrait search, **Checked** / **Fix it** / **More** / **Clear** / **Upload**).
@@ -45,8 +45,11 @@ Gallery/
 │   │   ├── components/ArtistBio.tsx         # Biography + portrait debug panel
 │   │   ├── components/DebugSearchResultsModal.tsx  # “More” search picker (20 results)
 │   │   ├── components/Timeline.tsx          # Era bar, year ticks, event markers
-│   │   ├── components/TimelineEventGuides.tsx  # Event vertical guides into movement flow
+│   │   ├── components/Timeline.tsx            # Classic horizontal era bar
+│   │   ├── components/VerticalTimeline.tsx    # Bottom-up vertical era rail
 │   │   ├── components/MovementBands.tsx   # Movement flow (SVG streams + branches)
+│   │   ├── components/VerticalMovementBands.tsx  # Bottom-up movement streams
+│   │   ├── components/TimelineEventGuides.tsx  # Event vertical guides into movement flow
 │   │   ├── components/CatalogSearchBar.tsx  # Timeline header catalog search
 │   │   ├── components/PaintingAnnotations.tsx  # Art-history notes on painting detail
 │   │   ├── pages/CheckupPage.tsx            # Image audit table
@@ -170,14 +173,19 @@ Implementation: `goToTimelineHome()` in `HomePage.tsx` — do not use the browse
 
 ## Timeline and movement flow
 
-The home page shows two linked views over the **same year window** (`viewStart` / `viewEnd` in `HomePage.tsx`):
+The home page shows two linked views over the **same year window** (`viewStart` / `viewEnd` in `HomePage.tsx`). A header link switches between layouts:
+
+| Layout | Era rail | Movement flow | Time direction |
+|--------|----------|---------------|----------------|
+| **Classic** (default) | `Timeline.tsx` (top bar) | `MovementBands.tsx` | Left → right |
+| **Vertical** | `VerticalTimeline.tsx` (left rail) | `VerticalMovementBands.tsx` (streams + lineage branches; no portraits) | Bottom → top |
 
 | View | Component | Purpose |
 |------|-----------|---------|
-| Era bar | `Timeline.tsx` | Historical eras, major event markers, click-to-zoom |
-| Movement flow | `MovementBands.tsx` | Curved streams per movement, lineage branches, artist portraits |
+| Era bar / rail | `Timeline.tsx` / `VerticalTimeline.tsx` | Historical eras, major event markers, click-to-zoom |
+| Movement flow | `MovementBands.tsx` / `VerticalMovementBands.tsx` | Streams per movement, artist portraits (classic also draws lineage branches) |
 
-Both views share zoom/pan behaviour via `client/src/utils/timelineView.ts` (`zoomTimelineView`, `panTimelineView`, `chooseTimelineTickInterval`, `createViewChangeScheduler`). The home page uses a **fixed viewport** (`100vh`): timeline + movement flow sit in a shared `home-timeline-stack` so event guide lines can extend from the era bar down through the movement canvas. The movement flow compresses vertically so all movements in the visible year range fit without page scrolling.
+Both layouts share zoom/pan behaviour via `client/src/utils/timelineView.ts` (`zoomTimelineView`, `panTimelineView`, `chooseTimelineTickInterval`, `createViewChangeScheduler`). The home page uses a **fixed viewport** (`100vh`). Classic stacks timeline above movements; vertical places the year rail beside the flow (`home-timeline-stack-vertical`).
 
 ### Catalog search (timeline header)
 
@@ -347,7 +355,7 @@ Enter from the home page by clicking a **movement name** on the movement flow. F
 | Period details | `MovementHallDetails.tsx` — classical / neoclassical use **shallow engaged corner pilasters** (never freestanding mid-hall or proud corner shafts that cover frames); `byzantine` adds engaged porphyry colonnettes with basket capitals, a marble revetment dado, and hanging brass polycandela; `gothic` adds bay-spaced compound piers with vault springers, transverse ribs arching across the nave, and a moulded string course — all flush to the side walls |
 | 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 emissive fixtures as artist halls when `has_influence_links` is true |
+| Influence lamps | Same golden upside-down emissive fixtures as artist halls when `has_influence_links` is true (shared rail: 40 cm above the tallest frame in the wing) |
 | 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 |