v0.1.2: Preferences page, About page, full icon set, redesigned edit form

- Rework the add/edit form onto a generic, catalog-driven field model
  (JobFieldCatalog + JobEditModel), replacing the old hand-written
  ApplicationEditDialog with ApplicationEditPage
- Add a Preferences page (reachable from the hamburger menu) with a
  KColorSchemeManager-backed color scheme switcher
- Add an About page reading from KAboutData
- Ship a full hicolor icon set (16-128px + scalable) via ecm_install_icons
  instead of a single flat SVG
- Restyle the edit form after KDE System Settings' Audio page:
  Kirigami.ListSectionHeader per category, flat separated rows, no card
  borders
- Explicitly declare Kirigami/KirigamiAddons/ColorScheme as CMake
  dependencies instead of relying on the QML import scanner alone
- Add KDEClangFormat/KDEGitCommitHooks, a CMakePresets.json, and a
  REUSE + clang-format lint CI workflow
- Reformat SPDX headers to include copyright, remove debug screenshot
  scaffolding

CMakePresets.json

@@ -0,0 +1,20 @@
+{
+    "version": 6,
+    "cmakeMinimumRequired": {
+        "major": 3,
+        "minor": 23,
+        "patch": 0
+    },
+    "configurePresets": [
+        {
+            "name": "ninja-dev",
+            "displayName": "Ninja (dev)",
+            "generator": "Ninja",
+            "binaryDir": "${sourceDir}/build",
+            "cacheVariables": {
+                "CMAKE_BUILD_TYPE": "Debug",
+                "BUILD_TESTING": "ON"
+            }
+        }
+    ]
+}