fix(hachidori): finish character dictionary imports without keep-alive w

- Close lingering sockets on the one-shot dictionary ZIP server so imports report completion as soon as the archive is read
- Run test:dictionary:electron in the Linux CI E2E job
- Note that annotations and lookups pause during Hachidori imports
- Keep only dictionaryBackend in the Dictionary Lookup settings section
- Move the requestHachidoriSharing import below the license header

changes/hachidori-backend.md

@@ -10,5 +10,6 @@ area: dictionary
 - First-run setup remembers each backend that finished it, including when reopened for legacy plugin cleanup, so switching back does not repeat setup, and the launcher gates playback on the backend the running app started with. Current incomplete or cancelled setup takes precedence over stale completion history. A running Yomitan session keeps using its external profile until it restarts into Hachidori.
 - Stats dashboard mining and deck lookup use the selected backend, with the Anki proxy enabled or disabled. Dashboard cards retain the selected history line and media instead of being processed again with the current mpv subtitle, with both Yomitan and Hachidori. Stats cards carry a `SubMiner::Stats` tag so polling also preserves their context. Hachidori word mining supplies dictionary aliases, IDs, and frequency metadata to its native Anki renderer. Settings labels for popup pause and the dictionary deck no longer name Yomitan, and the backend selector sits with the other dictionary settings.
 - Hachidori scans, dictionary counts, and settings reads wait for the dictionary engine to finish loading or importing instead of caching empty results.
+- Character dictionary imports report completion as soon as the archive is read instead of waiting out the temporary server's keep-alive timeout.
 - First-run setup can link an external Hachidori dictionary host in an app, browser, or Docker container, verify its library, and unlink back to local dictionaries. The optional host controls are collapsed by default and explain which apps or containers must stay running. Unresponsive connection checks time out so setup remains usable. Anki mining, media enrichment, and custom toolbar buttons stay in SubMiner, including when editing buttons while linked.
 - Hachidori frequency highlighting reuses dictionary-entry ranks and fills missing ranks through its existing API. Entries without a matching definition may remain unranked. The bundled integration is maintained in a pinned fork submodule using upstream HoshiDicts and WASM binaries.