feat: add favicons, drag-to-reorder sites, and SVG support

- Load site favicons (svg → png → ico fallback) via Coil 3 with
  SubcomposeAsyncImage; globe icon as final fallback
- Register SvgDecoder in ImplausiblyApp for SVG favicon support
- Add drag-to-reorder via sh.calvin.reorderable library with a
  drag handle per site row; order persisted to sort_order column
- Add sort_order column to stored_sites with schema migration (1.sqm)
- New SiteRepository methods: reorderSites(), deleteSitesForInstance(),
  getAllSites() now includes sort_order
- Dependencies: coil-compose, coil-network-okhttp, coil-svg,
  reorderable (all Apache 2.0)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

gradle/libs.versions.toml

@@ -25,6 +25,12 @@ ktor = "3.0.3"
 # SQLDelight
 sqldelight = "2.0.2"
 
+# Coil
+coil = "3.0.4"
+
+# Reorderable
+reorderable = "2.4.3"
+
 # Testing
 junit = "4.13.2"
 mockk = "1.13.13"
@@ -70,6 +76,14 @@ ktor-client-mock = { group = "io.ktor", name = "ktor-client-mock", version.ref =
 sqldelight-android-driver = { group = "app.cash.sqldelight", name = "android-driver", version.ref = "sqldelight" }
 sqldelight-coroutines = { group = "app.cash.sqldelight", name = "coroutines-extensions", version.ref = "sqldelight" }
 
+# Coil
+coil-compose = { group = "io.coil-kt.coil3", name = "coil-compose", version.ref = "coil" }
+coil-network-okhttp = { group = "io.coil-kt.coil3", name = "coil-network-okhttp", version.ref = "coil" }
+coil-svg = { group = "io.coil-kt.coil3", name = "coil-svg", version.ref = "coil" }
+
+# Reorderable
+reorderable = { group = "sh.calvin.reorderable", name = "reorderable", version.ref = "reorderable" }
+
 # Serialization
 kotlinx-serialization-json = { group = "org.jetbrains.kotlinx", name = "kotlinx-serialization-json", version.ref = "kotlinx-serialization" }