Remove wall spots

Wall spots were markers for where SteamVR panels/windows could dock on a
home's walls (Meta's WallPlacementComponent). Removed the feature end to
end: the WorldWallSpot type and its JSON/binary serialization, the loader
that read WallPlacementComponent, auto-generation of spots and the hotspots
placed in front of them, the Studio editor's Wall Spot kind (Add menu,
properties, overlay draw, picking, selection, report), the debug overlay,
the home report counts, and the walktest viz. The PanelDock subsystem
(src/panel_dock.h) existed only to dock panels onto wall spots and is
deleted with its use in Frame Home's frame loop.

Baked scene format is bumped to v14: new bakes omit wall spots, and older
baked scenes still load (the wall-spot block is read past). Collision walls
(WorldCollider::Wall) are unaffected — only the panel-placement markers are
gone. Docs updated.

Note: the pre-existing FRAME_HOME_PC Windows build break in walkgrid.h
(the `near` macro) is unrelated and left as-is.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/walktest/walkviz.cpp

@@ -164,8 +164,8 @@ int main(int argc, char** argv) {
             std::printf("   lost cells: %d\n", lost);
             std::printf("   re-baked with the walls and objects: %.1f m2 (was %.1f)\n", r2.walkArea, r.walkArea);
         }
-        std::printf("   generated in %.1f ms: %zu walls, %zu objects, %zu seats, %zu wall spots, %zu hotspots\n", std::chrono::duration<double, std::milli>(std::chrono::steady_clock::now() - t0).count(),
-                    gr.walls.size(), gr.objects.size(), gr.seats.size(), gr.spots.size(), gr.hotspots.size());
+        std::printf("   generated in %.1f ms: %zu walls, %zu objects, %zu seats, %zu hotspots\n", std::chrono::duration<double, std::milli>(std::chrono::steady_clock::now() - t0).count(),
+                    gr.walls.size(), gr.objects.size(), gr.seats.size(), gr.hotspots.size());
         auto line = [&](float x0, float z0, float x1, float z1, int R, int G, int B) {
             const int n = static_cast<int>(std::hypot(x1 - x0, z1 - z0) / g->p.cell * px) + 1;
             for (int i = 0; i <= n; ++i) {
@@ -192,12 +192,6 @@ int main(int argc, char** argv) {
                 const float xa = v[0], xb = v[3], za = v[2], zb = v[14];
                 line(xa, za, xb, za, 40, 160, 255); line(xb, za, xb, zb, 40, 160, 255); line(xb, zb, xa, zb, 40, 160, 255); line(xa, zb, xa, za, 40, 160, 255);
             }
-        for (const WorldWallSpot& w : gr.spots) {
-            const float hx = w.width * 0.5f, ux = w.world[0], uz = w.world[2];
-            line(w.world[12] - ux * hx, w.world[14] - uz * hx, w.world[12] + ux * hx, w.world[14] + uz * hx, 255, 230, 0);
-            line(w.world[12], w.world[14], w.world[12] + w.world[8] * 0.6f, w.world[14] + w.world[10] * 0.6f, 255, 230, 0);
-            std::printf("   wall spot %.1f x %.1f m at (%.2f %.2f %.2f)\n", w.width, w.height, w.world[12], w.world[13], w.world[14]);
-        }
         for (const WorldPoint& p : gr.seats) {
             const float fx = -std::sin(p.yaw), fz = -std::cos(p.yaw);
             line(p.pos[0] - 0.15f, p.pos[2], p.pos[0] + 0.15f, p.pos[2], 255, 0, 255);

tools/walktest/worldrender.cpp

@@ -1,6 +1,6 @@
 // Renders a home headlessly (lavapipe: VK_ICD_FILENAMES=/usr/share/vulkan/icd.d/lvp_icd.json) with its walkable area
 // and World > Auto-generate's items drawn over it as Frame Studio's guide pass does:
-//   walkable area green, walls red boxes, seats magenta posts + facing bar, wall spots yellow panels, hotspots cyan posts
+//   walkable area green, walls red boxes, seats magenta posts + facing bar, hotspots cyan posts
 // worldrender <apk[+vista]> <out-prefix> [size] [x,y,z,yaw,pitch ...]   (no views: four from above the area's corners)
 #include "hsl_renderer.h"
 #include "hsl_scene.h"
@@ -49,7 +49,7 @@ int main(int argc, char** argv) {
     w.walkGridCache = bakeWalkGrid(scene, w, WalkParams{});
     const WalkGrid& g = *w.walkGridCache;
     const GenResult gen = generateWorldItems(g, w, drawnWalkSources(scene, w, nullptr, nullptr, false));
-    std::printf("%zu walls, %zu seats, %zu wall spots, %zu hotspots\n", gen.walls.size(), gen.seats.size(), gen.spots.size(), gen.hotspots.size());
+    std::printf("%zu walls, %zu seats, %zu hotspots\n", gen.walls.size(), gen.seats.size(), gen.hotspots.size());
 
     std::vector<GuideVertex> v;
     auto vert = [&](const float* p, const float* c) { GuideVertex q; std::memcpy(q.pos, p, 12); std::memcpy(q.rgba, c, 16); v.push_back(q); };
@@ -63,7 +63,7 @@ int main(int argc, char** argv) {
         static const int f[12][3] = {{0,1,3},{0,3,2},{4,6,7},{4,7,5},{0,4,5},{0,5,1},{2,3,7},{2,7,6},{0,2,6},{0,6,4},{1,5,7},{1,7,3}};
         for (auto& t : f) tri(p[t[0]], p[t[1]], p[t[2]], col);
     };
-    const float green[4] = {0.1f, 0.85f, 0.3f, 0.35f}, red[4] = {1, 0.15f, 0.1f, 0.55f}, mag[4] = {1, 0, 1, 0.9f}, yel[4] = {1, 0.9f, 0, 0.6f}, cyan[4] = {0, 0.9f, 1, 0.9f};
+    const float green[4] = {0.1f, 0.85f, 0.3f, 0.35f}, red[4] = {1, 0.15f, 0.1f, 0.55f}, mag[4] = {1, 0, 1, 0.9f}, cyan[4] = {0, 0.9f, 1, 0.9f};
     g.outline([&](const float* a, const float* b, const float* c, bool) {
         const float A[3] = {a[0], a[1] + 0.03f, a[2]}, B[3] = {b[0], b[1] + 0.03f, b[2]}, C[3] = {c[0], c[1] + 0.03f, c[2]};
         tri(A, B, C, green);
@@ -76,7 +76,6 @@ int main(int argc, char** argv) {
         const float m2[16] = {fz,0,-fx,0, 0,1,0,0, fx,0,fz,0, p.pos[0] + fx * 0.2f, p.pos[1] + 0.02f, p.pos[2] + fz * 0.2f, 1}, h2[3] = {0.03f, 0.02f, 0.2f};
         box(m2, h2, mag);
     }
-    for (const WorldWallSpot& s : gen.spots) { const float h[3] = {s.width * 0.5f, s.height * 0.5f, 0.02f}; box(s.world, h, yel); }
     for (const WorldPoint& p : gen.hotspots) {
         const float m[16] = {1,0,0,0, 0,1,0,0, 0,0,1,0, p.pos[0], p.pos[1] + 0.75f, p.pos[2], 1}, h[3] = {0.05f, 0.75f, 0.05f};
         box(m, h, cyan);
@@ -123,11 +122,6 @@ int main(int argc, char** argv) {
             const float fx = -std::sin(p.yaw), fz = -std::cos(p.yaw);
             cams.push_back({p.pos[0] + fx * 1.6f, p.pos[1] + 1.1f, p.pos[2] + fz * 1.6f, p.yaw * 57.2958f + 180, -28});
         }
-    if (mode == "spots")                                               // each wall spot from 2.5 m back
-        for (const WorldWallSpot& w : gen.spots) {
-            const float fx = w.world[8], fz = w.world[10];
-            cams.push_back({w.world[12] + fx * 2.5f, w.world[13], w.world[14] + fz * 2.5f, std::atan2(fx, fz) * 57.2958f, 0});
-        }
     if (cams.empty() && mode.empty()) {   // an overview from high over the area, then eye-level views from spots across it, both ways
         float lo[2] = {1e9f, 1e9f}, hi[2] = {-1e9f, -1e9f}, y = 0; int n = 0;
         for (int z = 0; z < g.nz; ++z) for (int x = 0; x < g.nx; ++x) for (const WalkSpan* s = g.begin(x, z); s != g.end(x, z); ++s)