feat: import Rnote notebooks (Issue #47)

The import (menu entry and drag & drop) now also accepts .rnote files
from Rnote 0.5.10 on, including the transformation and document config
layouts that changed in 0.13 and 0.15. Taken over: brush strokes with
their pressure curve, shapes as outlines, texts, bitmap images and SVG
images, which are rasterized with resvg (Rnote stores imported PDF
pages as SVG). Fixed-size and continuous documents keep their pages;
infinite ones become an endless notebook.

The parts shared with the Xournal++ import moved to src/import.rs.
resvg and its dependencies were added to the Flatpak cargo sources.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.lock

@@ -539,6 +539,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "data-url"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be1e0bca6c3637f992fc1cc7cbc52a78c1ef6db076dbf1059c4323d6a2048376"
+
 [[package]]
 name = "deranged"
 version = "0.5.8"
@@ -790,6 +796,12 @@ dependencies = [
  "zlib-rs",
 ]
 
+[[package]]
+name = "float-cmp"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "98de4bbd547a563b716d8dfa9aad1cb19bfab00f4fa09a6a4ed21dbcf44ce9c4"
+
 [[package]]
 name = "foldhash"
 version = "0.2.0"
@@ -1381,6 +1393,12 @@ dependencies = [
  "quick-error",
 ]
 
+[[package]]
+name = "imagesize"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "65b27460c2c92b037f3f94c538ed9a3342f3fdf923606781629ccb35f82d042a"
+
 [[package]]
 name = "indexmap"
 version = "2.14.2"
@@ -1414,6 +1432,7 @@ dependencies = [
  "pollster",
  "printpdf",
  "quick-xml",
+ "resvg",
  "semver",
  "serde",
  "serde_json",
@@ -2082,6 +2101,12 @@ dependencies = [
  "pxfm",
 ]
 
+[[package]]
+name = "pico-args"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5be167a7af36ee22fe3115051bc51f6e6c7054c9348e28deb4f49bd6f705a315"
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.17"
@@ -2329,6 +2354,33 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19b30a45b0cd0bcca8037f3d0dc3421eaf95327a17cad11964fb8179b4fc4832"
 
+[[package]]
+name = "resvg"
+version = "0.49.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1572844b6727a1bf842190e9947641a68ac44bed83f50afb4bd1407a2564bee8"
+dependencies = [
+ "bytemuck",
+ "gif",
+ "image-webp",
+ "log",
+ "pico-args",
+ "rgb",
+ "svgtypes",
+ "tiny-skia 0.12.0",
+ "usvg",
+ "zune-jpeg",
+]
+
+[[package]]
+name = "rgb"
+version = "0.8.53"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "47b34b781b31e5d73e9fbc8689c70551fd1ade9a19e3e28cfec8580a79290cc4"
+dependencies = [
+ "bytemuck",
+]
+
 [[package]]
 name = "ring"
 version = "0.17.14"
@@ -2343,6 +2395,15 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "roxmltree"
+version = "0.21.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9da7f59328b09405b181fee1018925fad50f157afb43c0c0f5c522c256dd5907"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "rustc-hash"
 version = "1.1.0"
@@ -2453,7 +2514,7 @@ dependencies = [
  "log",
  "memmap2",
  "smithay-client-toolkit",
- "tiny-skia",
+ "tiny-skia 0.11.4",
 ]
 
 [[package]]
@@ -2534,6 +2595,15 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e3a9fe34e3e7a50316060351f37187a3f546bce95496156754b601a5fa71b76e"
 
+[[package]]
+name = "simplecss"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a9c6883ca9c3c7c90e888de77b7a5c849c779d25d74a1269b0218b14e8b136c"
+dependencies = [
+ "log",
+]
+
 [[package]]
 name = "siphasher"
 version = "1.0.4"
@@ -2641,6 +2711,9 @@ name = "strict-num"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6637bab7722d379c8b41ba849228d680cc12d0a45ba1fa2b48f2a30577a06731"
+dependencies = [
+ "float-cmp",
+]
 
 [[package]]
 name = "strum"
@@ -2670,6 +2743,16 @@ version = "2.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "13c2bddecc57b384dee18652358fb23172facb8a2c51ccc10d74c157bdea3292"
 
+[[package]]
+name = "svgtypes"
+version = "0.16.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "695b5790b3131dafa99b3bbfd25a216edb3d216dad9ca208d4657bfb8f2abc3d"
+dependencies = [
+ "kurbo",
+ "siphasher",
+]
+
 [[package]]
 name = "syn"
 version = "1.0.109"
@@ -2831,7 +2914,22 @@ dependencies = [
  "bytemuck",
  "cfg-if",
  "log",
- "tiny-skia-path",
+ "tiny-skia-path 0.11.4",
+]
+
+[[package]]
+name = "tiny-skia"
+version = "0.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "47ffee5eaaf5527f630fb0e356b90ebdec84d5d18d937c5e440350f88c5a91ea"
+dependencies = [
+ "arrayref",
+ "arrayvec",
+ "bytemuck",
+ "cfg-if",
+ "log",
+ "png",
+ "tiny-skia-path 0.12.0",
 ]
 
 [[package]]
@@ -2845,6 +2943,17 @@ dependencies = [
  "strict-num",
 ]
 
+[[package]]
+name = "tiny-skia-path"
+version = "0.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "edca365c3faccca67d06593c5980fa6c57687de727a03131735bb85f01fdeeb9"
+dependencies = [
+ "arrayref",
+ "bytemuck",
+ "strict-num",
+]
+
 [[package]]
 name = "tinystr"
 version = "0.8.4"
@@ -2981,6 +3090,25 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "usvg"
+version = "0.49.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d09b73ee83641d390ad7ffd9000f347b16eb128e437675b6ff277ea5c7fcf22c"
+dependencies = [
+ "data-url",
+ "imagesize",
+ "kurbo",
+ "log",
+ "pico-args",
+ "roxmltree",
+ "simplecss",
+ "siphasher",
+ "strict-num",
+ "svgtypes",
+ "tiny-skia-path 0.12.0",
+]
+
 [[package]]
 name = "utf8_iter"
 version = "1.0.4"