Redesign the library UI and add scenario cover art

Rework the home page into a single landing surface and give the app a
consistent visual language, chosen as "illuminated tome" over two other
pitched directions because it builds on the existing Cinzel + gold identity
instead of replacing it.

Home is now Continue (up to 4 in-progress stories, each showing where you
left off) over a scenario shelf, each section with a "See all" link. The
full adventure list moves to /adventures.

Scenario cover art has three tiers, in precedence order: an uploaded picture
(downscaled client-side to 400px WebP before storing), an emoji, or gradient
art generated from a hash of the title so no card is ever an empty box.
Adventures inherit their scenario's art. Images live in the row rather than
on disk because Render's free tier has no persistent volume, and it keeps
export bundles self-contained; list responses carry a cacheable
/api/scenarios/{id}/image URL rather than the base64.

Also: ambient drifting motes behind the app, loading skeletons, staggered
card entrance, ornamental scene breaks and a drop cap in the story, a
"Weaving" thinking indicator, and a toast system replacing every alert().

Two fixes found along the way:

- Importing a scenario bundle with no "tags" key returned a 500. Column
  defaults are not applied until flush, so the attribute was still None
  when the width clamp sliced it.
- Anything meaning "the story's latest narration" was missing action type
  "start", which is the only text a freshly created adventure has, so new
  adventures looked empty. Collected as NARRATION_TYPES.

Migrations 30 and 31 add scenarios.image and scenarios.icon; both are
additive with a '' default and were verified against a database stamped at
29. vite.config.js now reads AIDND_API_PORT so the recurring port-8000
clash with another local app needs no file edit.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014FGY1yvzSeKgTtRfeVtDmx

backend/app/routers/scenarios.py

@@ -1,8 +1,9 @@
 from fastapi import APIRouter, Body, Depends, HTTPException, Request
+from fastapi.responses import Response
 from sqlalchemy import or_
 from sqlalchemy.orm import Session
 
-from .. import auth, limits, models, schemas
+from .. import auth, images, limits, models, schemas
 from ..database import get_db
 
 router = APIRouter(prefix="/api/scenarios", tags=["scenarios"])
@@ -55,6 +56,30 @@ def get_scenario(
     return get_scenario_or_404(scenario_id, db, user)
 
 
+@router.get("/{scenario_id}/image")
+def get_scenario_image(
+    scenario_id: int,
+    db: Session = Depends(get_db),
+    user: models.User = Depends(auth.get_current_user),
+):
+    """Serve an uploaded cover image as real bytes.
+
+    Lists point here instead of inlining the data URI. The response is marked
+    immutable and the URL carries a `?v=<updated_at>` stamp, so browsers cache
+    it indefinitely but pick up a new picture the moment the author saves one.
+    """
+    scenario = get_scenario_or_404(scenario_id, db, user)
+    decoded = images.decode(scenario.image)
+    if decoded is None:
+        raise HTTPException(404, "This scenario has no uploaded image")
+    data, content_type = decoded
+    return Response(
+        content=data,
+        media_type=content_type,
+        headers={"Cache-Control": "private, max-age=31536000, immutable"},
+    )
+
+
 @router.patch("/{scenario_id}", response_model=schemas.ScenarioOut)
 def update_scenario(
     scenario_id: int,
@@ -109,6 +134,8 @@ def export_scenario(
         "authorsNote": s.authors_note,
         "aiInstructions": s.ai_instructions,
         "tags": s.tags,
+        "image": s.image,
+        "icon": s.icon,
         "statSchema": s.stat_schema,
         "storyCards": [
             {"type": c.type, "name": c.name, "keys": c.keys, "entry": c.entry, "notes": c.notes}
@@ -138,8 +165,8 @@ _SCENARIO_KEYS = {
     "instructions": "ai_instructions",
 }
 _IGNORED_KEYS = {"format", "storyCards", "worldInfo", "worldInformation", "scripts", "tags",
-                 "statSchema", "stat_schema",
-                 "createdAt", "updatedAt", "id", "publicId", "image", "nsfw", "type", "options"}
+                 "statSchema", "stat_schema", "image", "icon",
+                 "createdAt", "updatedAt", "id", "publicId", "nsfw", "type", "options"}
 
 
 @router.post("/import", status_code=201)
@@ -171,13 +198,24 @@ def import_scenario(
     if isinstance(schema, dict):
         fields["stat_schema"] = schema
 
+    # AI Dungeon bundles carry an `image` too, so this is worth honouring — but
+    # it's untrusted input, hence sanitize() rather than a straight assignment.
+    image = images.sanitize(bundle.get("image"), schemas.IMAGE_MAX)
+    if image:
+        fields["image"] = image
+    icon = bundle.get("icon")
+    if isinstance(icon, str) and icon:
+        fields["icon"] = icon[:schemas.ICON_MAX]
+
     scenario = models.Scenario(**fields, user_id=user.id)
     if not scenario.title:
         scenario.title = "Imported Scenario"
     # Raw-dict import bypasses the schemas — clamp to VARCHAR widths
-    # (Postgres enforces them; see schemas.py).
+    # (Postgres enforces them; see schemas.py). Column defaults haven't been
+    # applied yet at this point (that happens at flush), so a bundle with no
+    # `tags` key leaves the attribute None — hence the `or ""`.
     scenario.title = scenario.title[:schemas.NAME_MAX]
-    scenario.tags = scenario.tags[:schemas.TAGS_MAX]
+    scenario.tags = (scenario.tags or "")[:schemas.TAGS_MAX]
     db.add(scenario)
     db.flush()