feat(dictionary): add Hachidori backend support

- Add backend selection, setup gating, Anki integration, and external host support
- Add launcher flags, documentation, packaging, and focused tests
- Open on-demand overlay modals on the first attempt

vendor/hachidori/scripts/store-sources.json

@@ -0,0 +1,29 @@
+[
+  {
+    "name": "libavif",
+    "revision": "1aadfad932c98c069a1204261b1856f81f3bc199",
+    "version": "1.3.0",
+    "url": "https://codeload.github.com/AOMediaCodec/libavif/tar.gz/1aadfad932c98c069a1204261b1856f81f3bc199",
+    "sha256": "ac93983be0cc7188ecfc654ecb77f886243edb3d3827fd45cca14c50b2d813e3",
+    "strip_prefix": "libavif-1aadfad932c98c069a1204261b1856f81f3bc199/",
+    "licenses": ["LICENSE"]
+  },
+  {
+    "name": "libaom",
+    "revision": "10aece4157eb79315da205f39e19bf6ab3ee30d0",
+    "version": "3.12.1",
+    "url": "https://storage.googleapis.com/aom-releases/libaom-3.12.1.tar.gz",
+    "sha256": "9e9775180dec7dfd61a79e00bda3809d43891aee6b2e331ff7f26986207ea22e",
+    "strip_prefix": "libaom-3.12.1/",
+    "licenses": ["LICENSE", "PATENTS", "third_party/libyuv/LICENSE", "third_party/fastfeat/LICENSE", "third_party/vector/LICENSE"]
+  },
+  {
+    "name": "zipjs",
+    "revision": "2.11.2",
+    "version": "2.11.2",
+    "url": "https://registry.npmjs.org/@zip.js/zip.js/-/zip.js-2.11.2.tgz",
+    "sha256": "82f90c0134fc02b4963187ab2b06299758c3f9e4dd678fbdacd082ea73f09d3e",
+    "strip_prefix": "package/",
+    "licenses": ["LICENSE"]
+  }
+]