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/lib/server.dart

@@ -43,13 +43,14 @@ Future<void> run(List<String> args) async {
       .pruneFiles();
 
   // The dictionaries in the server's folder, those that changed since; in
-  // the background, as loading takes a minute or two. Then again daily, as
-  // the dictionaries service replaces them weekly.
+  // the background, as loading takes a minute or two. Then again hourly, as
+  // the dictionaries service replaces them weekly (and fills its volume
+  // first after an instance's first start).
   unawaited(_loadDictionaries(pod));
   await pod.futureCalls.cancel(_dictionaryReload);
   await pod.futureCalls
       .callRecurring(identifier: _dictionaryReload)
-      .cron('7 4 * * *')
+      .cron('7 * * * *')
       .dictionaryReload
       .reloadDictionaries();
 }
@@ -73,5 +74,5 @@ const _pruning = 'prune-abandoned-anonymous-people';
 /// The identifier of the daily pruning of files.
 const _filePruning = 'prune-unreferenced-files';
 
-/// The identifier of the daily rereading of the dictionaries.
+/// The identifier of the hourly rereading of the dictionaries.
 const _dictionaryReload = 'reload-dictionaries';