docs(spec,driver-turso): the forced-replica D3 entry names the two doors; the README lists the sync-key refusals

The new D3 entry's surface named the driver's TursoConfigSchema mirror
among the surfaces that refuse a forced mode 'replica' with no syncUrl.
The mirror declares no mode key and strips an authored one, so it
cannot see a forced mode: it carries the arm's text for parity only.
The surface now names the two doors (the spec contract and the
constructor) and says what the mirror does. registry.ts regenerated by
gen:migration-registry.

The driver README's list of constructor refusals named only the url
refusals; it now also names the three sync-key refusals (syncUrl under
a forced remote mode, sync with no syncUrl, a forced replica with no
syncUrl). Text only.

Co-authored-by: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N8TPEsoJxPsdSdNKGnNGEN

Author: claude

packages/drivers/driver-turso/README.md

@@ -223,6 +223,18 @@ no embedded replica for a remote url anyway. For a remote database, drop
 no local engine, so its url is not judged here: `@libsql/client` refuses a
 url it cannot open when the driver connects.
 
+The constructor also refuses (`VALIDATION_ERROR` / 400) three sync settings
+that nothing would honour, each with the message `@objectstack/spec`'s
+`TursoConfigSchema` gives at authoring:
+
+- `syncUrl` under a forced `mode: 'remote'`, where the remote client never
+  receives it. For a remote database, drop `syncUrl` (and `sync`);
+- `sync` with no `syncUrl` (or an empty one), in any mode, where nothing reads
+  it. Set `syncUrl`, or remove `sync`;
+- a forced `mode: 'replica'` with no `syncUrl` (or an empty one), which would
+  never sync and would run as a plain local database. Name the remote in
+  `syncUrl` beside the `file:` url, or drop `mode` for a local database.
+
 You can also force a specific mode:
 
 ```typescript

packages/spec/src/migrations/entries/semantic/18.turso-config-forced-replica-without-sync-url-refused.ts

@@ -13,9 +13,11 @@ export const entry: SemanticMigration = {
   // No backticks in `surface` — build-upgrade-guide renders it inside a code
   // span already, and a nested backtick would close it.
   surface:
-    'data.TursoConfig (a turso / libsql datasource.config), the published TursoConfigSchema mirror '
-    + 'of @objectstack/driver-turso, and the TursoDriver constructor — mode replica with no syncUrl '
-    + '(or an empty one) is now refused, on mode',
+    'data.TursoConfig (a turso / libsql datasource.config) and the TursoDriver constructor of '
+    + '@objectstack/driver-turso — mode replica with no syncUrl (or an empty one) is now refused, on '
+    + 'mode at authoring and at construction. The published TursoConfigSchema mirror of '
+    + '@objectstack/driver-turso carries the same text for parity but declares no mode key and strips '
+    + 'an authored one, so it cannot see a forced mode and still accepts the config as a local file',
   replacement:
     'the configuration the author meant. An embedded replica names the remote it replicates from: '
     + 'keep the file: url and set syncUrl to the libsql or https Turso endpoint, for example url '

packages/spec/src/migrations/registry.ts

@@ -16071,9 +16071,11 @@ const step18: MigrationStep = {
       // No backticks in `surface` — build-upgrade-guide renders it inside a code
       // span already, and a nested backtick would close it.
       surface:
-        'data.TursoConfig (a turso / libsql datasource.config), the published TursoConfigSchema mirror '
-        + 'of @objectstack/driver-turso, and the TursoDriver constructor — mode replica with no syncUrl '
-        + '(or an empty one) is now refused, on mode',
+        'data.TursoConfig (a turso / libsql datasource.config) and the TursoDriver constructor of '
+        + '@objectstack/driver-turso — mode replica with no syncUrl (or an empty one) is now refused, on '
+        + 'mode at authoring and at construction. The published TursoConfigSchema mirror of '
+        + '@objectstack/driver-turso carries the same text for parity but declares no mode key and strips '
+        + 'an authored one, so it cannot see a forced mode and still accepts the config as a local file',
       replacement:
         'the configuration the author meant. An embedded replica names the remote it replicates from: '
         + 'keep the file: url and set syncUrl to the libsql or https Turso endpoint, for example url '