Security fix for path-traversal attack (#48)

Additionally:

- Make expense and budget modal "reset" once closed, saved, or deleted.
- Make manifest icons dark
- Budgets in small screens should be full-screen
- Minor code cleanup

Fixes #48

static/images/favicon-dark.svg

@@ -0,0 +1,121 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   data-v-fde0c5aa=""
+   viewBox="0 0 80 80"
+   class="iconLeft"
+   version="1.1"
+   id="svg3"
+   sodipodi:docname="favicon-dark.svg"
+   inkscape:export-filename="favicon-dark.png"
+   inkscape:export-xdpi="1228.8"
+   inkscape:export-ydpi="1228.8"
+   inkscape:version="1.3.2 (091e20e, 2023-11-25)"
+   width="80"
+   height="80"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:xlink="http://www.w3.org/1999/xlink"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:svg="http://www.w3.org/2000/svg">
+  <sodipodi:namedview
+     id="namedview3"
+     pagecolor="#ffffff"
+     bordercolor="#000000"
+     borderopacity="0.25"
+     inkscape:showpageshadow="2"
+     inkscape:pageopacity="0.0"
+     inkscape:pagecheckerboard="0"
+     inkscape:deskcolor="#d1d1d1"
+     inkscape:zoom="1.92"
+     inkscape:cx="67.96875"
+     inkscape:cy="15.104167"
+     inkscape:window-width="1312"
+     inkscape:window-height="449"
+     inkscape:window-x="0"
+     inkscape:window-y="38"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="g5" />
+  <!---->
+  <defs
+     data-v-fde0c5aa=""
+     id="defs1">
+    <!---->
+    <linearGradient
+       inkscape:collect="always"
+       xlink:href="#d27698e6-eb24-4a3f-96af-256d84d5b3ea"
+       id="linearGradient4"
+       gradientTransform="scale(1.3465159,0.74265739)"
+       x1="0"
+       y1="0"
+       x2="74.265739"
+       y2="0"
+       gradientUnits="userSpaceOnUse" />
+    <linearGradient
+       inkscape:collect="always"
+       xlink:href="#d27698e6-eb24-4a3f-96af-256d84d5b3ea"
+       id="linearGradient5"
+       gradientTransform="scale(1.3465159,0.74265739)"
+       x1="0"
+       y1="0"
+       x2="74.265739"
+       y2="0"
+       gradientUnits="userSpaceOnUse" />
+  </defs>
+  <defs
+     data-v-fde0c5aa=""
+     id="defs2">
+    <!---->
+  </defs>
+  <defs
+     data-v-fde0c5aa=""
+     id="defs3">
+    <linearGradient
+       data-v-fde0c5aa=""
+       gradientTransform="rotate(25)"
+       id="d27698e6-eb24-4a3f-96af-256d84d5b3ea"
+       x1="0"
+       y1="0"
+       x2="1"
+       y2="0">
+      <stop
+         data-v-fde0c5aa=""
+         offset="0%"
+         stop-color="#51A4FB"
+         stop-opacity="1"
+         id="stop2" />
+      <stop
+         data-v-fde0c5aa=""
+         offset="100%"
+         stop-color="#51A4FB"
+         stop-opacity="1"
+         id="stop3" />
+    </linearGradient>
+  </defs>
+  <g
+     id="g5"
+     transform="translate(-24.999993,-125)">
+    <rect
+       data-v-fde0c5aa=""
+       fill="#e6f2fe"
+       x="24.999992"
+       y="125"
+       width="80"
+       height="80"
+       class="logo-background-square"
+       id="rect1"
+       style="stroke-width:0.266666;fill:#02203a;fill-opacity:1" />
+    <g
+       data-v-fde0c5aa=""
+       id="f64f14cc-5390-468e-9cd6-ee0163dcbf09"
+       stroke="none"
+       fill="url(#d27698e6-eb24-4a3f-96af-256d84d5b3ea)"
+       transform="matrix(0.60062915,0,0,0.60062915,34.968536,148.43645)"
+       style="fill:url(#linearGradient5)">
+      <path
+         d="M 77.959,55.154 H 11.282 C 5.061,55.154 0,50.093 0,43.873 0,38.595 3.643,34.152 8.546,32.927 10.734,27.458 15.794,23.541 21.695,22.838 22.317,10.14 32.843,0 45.693,0 55.11,0 63.515,5.536 67.416,13.756 a 21.944,21.944 0 0 1 10.543,-2.682 c 12.153,0 22.041,9.887 22.041,22.04 0,12.153 -9.887,22.04 -22.041,22.04 z M 11.209,40.372 a 3.507,3.507 0 0 0 -3.429,3.501 3.504,3.504 0 0 0 3.501,3.501 h 66.678 c 7.863,0 14.26,-6.397 14.26,-14.26 0,-7.863 -6.396,-14.259 -14.26,-14.259 -3.683,0 -7.18,1.404 -9.847,3.952 L 63.016,27.678 61.612,20.77 C 60.083,13.243 53.388,7.78 45.693,7.78 c -8.958,0 -16.247,7.288 -16.247,16.246 0,0.728 0.054,1.483 0.159,2.246 l 0.73,5.287 -5.256,-0.923 a 8.59,8.59 0 0 0 -1.474,-0.132 c -4.002,0 -7.479,2.842 -8.267,6.757 l -0.65,3.227 -3.29,-0.106 z"
+         id="path3"
+         style="fill:url(#linearGradient4)" />
+    </g>
+  </g>
+  <!---->
+</svg>