Carry Toad's retired prompt preferences; track formbridge main in the stack

tools/cutover/carry_toad_input_settings.py

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+"""Carry the retired prompt preferences into Toad's input box settings group."""
+
+from dataclasses import dataclass
+from typing import Annotated
+
+from pydantic import JsonValue
+
+from agent_comms.errors import RelationViolationError
+from agent_comms.field_codec import FieldCodec, WireName
+from cutover.carry_toad_key_mode import ToadSettingsCarry
+from toad.preferences import InputSettings, ToadSettings, UiSettings
+from toad.setting_choices import FlushInputBox, InputBox
+
+
+@dataclass(frozen=True)
+class PreviousCompactInput:
+    """The retired flag only. True removed the prompt's spacing, which is now Flush."""
+
+    compact_input: Annotated[bool, WireName("compact-input")]
+
+
+@dataclass(frozen=True)
+class PreviousPromptMessage:
+    """The retired placeholder text, which no widget read; it is now the live placeholder."""
+
+    prompt_message: str
+
+
+class ToadInputSettings(ToadSettingsCarry):
+    def rewrite(self, document: dict[str, JsonValue]) -> int:
+        ui_key = FieldCodec.record_key(ToadSettings, "ui")
+        ui = FieldCodec.decode(dict[str, JsonValue], document.get(ui_key, {}))
+        compact_key = FieldCodec.record_key(PreviousCompactInput, "compact_input")
+        message_key = FieldCodec.record_key(PreviousPromptMessage, "prompt_message")
+        if compact_key not in ui and message_key not in ui:
+            return 0
+        input_key = FieldCodec.record_key(UiSettings, "input")
+        if input_key in ui:
+            raise RelationViolationError("Both old and current prompt preferences exist")
+        carried: dict[str, JsonValue] = {}
+        if compact_key in ui:
+            previous = FieldCodec.decode(PreviousCompactInput, {compact_key: ui.pop(compact_key)})
+            if previous.compact_input:
+                carried[FieldCodec.record_key(InputSettings, "box")] = FieldCodec.encode(
+                    FlushInputBox, type[InputBox]
+                )
+        if message_key in ui:
+            previous_message = FieldCodec.decode(
+                PreviousPromptMessage, {message_key: ui.pop(message_key)}
+            )
+            carried[FieldCodec.record_key(InputSettings, "placeholder")] = (
+                previous_message.prompt_message
+            )
+        if carried:
+            ui[input_key] = carried
+        document[ui_key] = ui
+        return 1