feat: editor improvements and collapsible sidebars

Add collapse/expand toggle for the AppShell navigation sidebar and the
editor properties panel (both persisted to localStorage). Bundles other
in-progress editor work including position anchors, outlet sizing, PBR
textures, window slope/frame depth, curtain metadata, and various 2D/3D
rendering tweaks.

scripts/fetch-textures.py

@@ -0,0 +1,134 @@
+#!/usr/bin/env python
+"""
+Download CC0 PBR texture sets from ambientCG and resize them to 512px JPEGs
+suitable for the house-plan-maker 3D view. Outputs land in
+apps/client/public/textures/{floors,walls}/<slug>/{color,normal,roughness}.jpg
+
+Texture credit: ambientCG (https://ambientcg.com), CC0 1.0 Universal.
+
+Run from repo root:
+    py -3 scripts/fetch-textures.py
+
+Re-running is idempotent — files are skipped if they already exist.
+"""
+
+import io
+import os
+import sys
+import urllib.request
+import zipfile
+from pathlib import Path
+
+try:
+    from PIL import Image
+except ImportError:
+    print("ERROR: PIL/Pillow is required. Install with: py -3 -m pip install pillow", file=sys.stderr)
+    sys.exit(1)
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+OUT_ROOT = REPO_ROOT / "apps" / "client" / "public" / "textures"
+TARGET_SIZE = 512
+
+# Map our enum values to ambientCG asset ids. The names follow the
+# Camera/Wood/Tile/etc. categories on https://ambientcg.com.
+FLOORS = {
+    # FloorType -> ambientCG asset
+    "CONCRETE": "Concrete034",
+    "WOOD_LIGHT": "WoodFloor043",
+    "WOOD_MEDIUM": "WoodFloor041",
+    "WOOD_DARK": "WoodFloor051",
+    "WOOD_HERRINGBONE": "WoodFloor057",
+    "TILE_WHITE": "Tiles074",
+    "TILE_GRAY": "Tiles101",
+    "LAMINATE": "WoodFloor044",
+}
+
+WALLS = {
+    # WallFinish -> ambientCG asset (PAINT skips textures, uses wallColor)
+    "PLASTER": "Plaster001",
+    "BRICK": "Bricks023",
+    "CONCRETE": "Concrete019",
+    "WOOD_PANEL": "WoodSiding001",
+    "WALLPAPER": "Fabric030",
+}
+
+# Maps we want from each set. ambientCG file naming: <Asset>_1K-JPG_<Map>.jpg
+MAPS = {
+    "color": "Color",
+    "normal": "NormalGL",
+    "roughness": "Roughness",
+}
+
+
+def download_zip(asset_id: str) -> bytes:
+    url = f"https://ambientcg.com/get?file={asset_id}_1K-JPG.zip"
+    print(f"  fetching {url}")
+    req = urllib.request.Request(url, headers={"User-Agent": "house-plan-maker/1.0"})
+    with urllib.request.urlopen(req, timeout=60) as resp:
+        return resp.read()
+
+
+def extract_and_resize(zip_bytes: bytes, asset_id: str, out_dir: Path) -> bool:
+    out_dir.mkdir(parents=True, exist_ok=True)
+    try:
+        zf = zipfile.ZipFile(io.BytesIO(zip_bytes))
+    except zipfile.BadZipFile:
+        # Server returned an HTML error page, not a zip.
+        print(f"  ERROR: {asset_id} did not return a zip — preview: {zip_bytes[:120]!r}")
+        return False
+
+    names = {n.lower(): n for n in zf.namelist()}
+    success = True
+
+    for out_name, ambient_map in MAPS.items():
+        out_path = out_dir / f"{out_name}.jpg"
+        if out_path.exists():
+            print(f"  skip (exists): {out_path.relative_to(REPO_ROOT)}")
+            continue
+        # Find the matching file in the zip (case-insensitive substring match).
+        needle = f"_{ambient_map}.jpg".lower()
+        match_lower = next((k for k in names if k.endswith(needle)), None)
+        if not match_lower:
+            print(f"  WARN: no {ambient_map} map in {asset_id}")
+            success = False
+            continue
+        with zf.open(names[match_lower]) as src:
+            img = Image.open(src)
+            img = img.convert("RGB")
+            img = img.resize((TARGET_SIZE, TARGET_SIZE), Image.LANCZOS)
+            img.save(out_path, "JPEG", quality=82, optimize=True)
+        print(f"  wrote {out_path.relative_to(REPO_ROOT)} ({out_path.stat().st_size // 1024} KB)")
+
+    return success
+
+
+def fetch_set(category: str, label: str, asset_id: str) -> None:
+    out_dir = OUT_ROOT / category / label.lower()
+    print(f"[{category}/{label}] -> {asset_id}")
+    # Skip whole asset if all three target files already exist.
+    if all((out_dir / f"{m}.jpg").exists() for m in MAPS):
+        print(f"  all maps already present, skipping fetch")
+        return
+    try:
+        zip_bytes = download_zip(asset_id)
+    except Exception as e:
+        print(f"  ERROR fetching {asset_id}: {e}")
+        return
+    extract_and_resize(zip_bytes, asset_id, out_dir)
+
+
+def main() -> None:
+    print(f"writing to {OUT_ROOT}")
+    OUT_ROOT.mkdir(parents=True, exist_ok=True)
+
+    for label, asset_id in FLOORS.items():
+        fetch_set("floors", label, asset_id)
+
+    for label, asset_id in WALLS.items():
+        fetch_set("walls", label, asset_id)
+
+    print("done.")
+
+
+if __name__ == "__main__":
+    main()