feat: a dictionary's corrections reach the cards made from it, by offer

Every dictionary entry now has a version: 16 hex digits of the SHA-256 of
what cards take of it (headword, reading, entry), made by the loader and
carried on every hit. A card keeps the version it took (card schema 8).
DictionaryEndpoint.changed returns, of the entries named with the
versions cards keep (1,000 at most a call; the app asks 500 at a time),
those whose version is another now.

The card browser says how many cards are behind their dictionary and takes
the corrections at a tap (decided 2026-10-09: by offer, never by
themselves). Taking one writes the entry as it is now over the revision
in which the card last took it, beside whatever came after, so the
revisions merge per side as two devices' edits do (ADR 0003): a side only
the dictionary changed takes the correction, a side the person changed
too is a conflict settled in the composer, whose words now name that
case. Cards made before versions are never offered one.

The server rereads its dictionary folder hourly now, not daily: the
dictionaries service fills its volume after an instance's first start,
and an hour with nothing changed costs a hash of each file.

Migration 20261009145434785-dictionary-entry-version: adds
dictionary_entry.version, text NOT NULL DEFAULT '' (rows loaded before
have none and are never reported as corrected), and by hand empties
dictionary_source."fileHash", so every source loads once more and its
entries get their versions; the schema stays as definition.sql says. The
old server goes on working until the switch.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MMm7usAo6q9ZZRoPkWjoxi
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_server/README.md

@@ -14,8 +14,8 @@ When you are finished, you can shut down the running server with `Q`.
 The dictionaries people look words up in (JMdict, …) are reference data the
 server holds for everyone. They come as dictionary files, which
 `halkyon_learn_curator` makes from the sources' downloads (its README says how).
-At every start, and daily at 04:07, the server loads the files in its
-`dictionaries` folder that changed since they were last loaded (by their
+At every start, and every hour at seven past, the server loads the files in
+its `dictionaries` folder that changed since they were last loaded (by their
 SHA-256): in the background, a source at a time, and all at once, so searches
 meanwhile still find the old entries. A file it can't read is logged and left
 out. `DICTIONARIES_DIR` names another folder.
@@ -27,12 +27,12 @@ once a month:
   `deploy/compose.yaml` (the curator, in a container of its own) downloads
   EDRDG's files of the day once its files are a week old, converts them, and
   replaces them in a volume the server reads (`curate update`, the curator's
-  README); the server takes them up the next morning. To supply files yourself
+  README); the server takes them up within the hour. To supply files yourself
   instead, remove the service and mount `deploy/dictionaries/` into the server
   (`compose.yaml` says how), and update them monthly.
 - **Development:** `dart run halkyon_learn_curator:curate update --into
   ../halkyon_learn_server/dictionaries` in the curator's folder (about a
-  minute), then restart `serverpod start`, or wait for the morning.
+  minute); the server takes them up within the hour.
 
 JMdict in English, with the JLPT levels and Tatoeba's example sentences, is
 about 20 MB gzipped and takes the server half a minute to load (219,000