refactor(core): simplify word validity error handling on recovery

diff --git a/core/src/apps/management/recovery_device/homescreen.py b/core/src/apps/management/recovery_device/homescreen.py
index 6b1b960f..d6b1face 100644
--- a/core/src/apps/management/recovery_device/homescreen.py
+++ b/core/src/apps/management/recovery_device/homescreen.py
@@ -94,6 +94,8 @@ async def _continue_recovery_process() -> Success:
     from trezor.enums import RecoveryType
     from trezor.errors import MnemonicError
 
+    from .word_validity import WordValidityResult
+
     # gather the current recovery state from storage
     recovery_type = storage_recovery.get_type()
     word_count, backup_type = recover.load_slip39_state()
@@ -130,7 +132,12 @@ async def _continue_recovery_process() -> Success:
         assert word_count is not None
 
         # ask for mnemonic words one by one
-        words = await layout.request_mnemonic(word_count, backup_type)
+        try:
+            # returns `None` on cancellation
+            words = await layout.request_mnemonic(word_count, backup_type)
+        except WordValidityResult as exc:
+            await exc.show_error()
+            words = None
 
         # if they were invalid or some checks failed we continue and request them again
         if not words:
diff --git a/core/src/apps/management/recovery_device/layout.py b/core/src/apps/management/recovery_device/layout.py
index a03f4281..88d25e33 100644
--- a/core/src/apps/management/recovery_device/layout.py
+++ b/core/src/apps/management/recovery_device/layout.py
@@ -30,6 +30,12 @@ if TYPE_CHECKING:
 async def request_mnemonic(
     word_count: int, backup_type: BackupType | None
 ) -> str | None:
+    """
+    Loops until a mnemonic is entered.
+
+    Returns a space-separated mnemonic on success, None on cancellation.
+    Raises `WordValidityResult` on share-related error.
+    """
     from trezor.ui.layouts.recovery import request_word
 
     from . import word_validity
@@ -68,21 +74,9 @@ async def request_mnemonic(
 
         i += 1
 
-        try:
-            non_empty_words = [word for word in words if word]
-            word_validity.check(backup_type, non_empty_words)
-        except word_validity.AlreadyAdded:
-            # show_share_already_added
-            await show_already_added()
-            return None
-        except word_validity.IdentifierMismatch:
-            # show_identifier_mismatch
-            await show_identifier_mismatch()
-            return None
-        except word_validity.ThresholdReached:
-            # show_group_threshold_reached
-            await show_group_threshold()
-            return None
+        non_empty_words = [word for word in words if word]
+        # raises `WordValidityResult` on error.
+        word_validity.check(backup_type, non_empty_words)
 
     return " ".join(words)
 
diff --git a/core/src/apps/management/recovery_device/word_validity.py b/core/src/apps/management/recovery_device/word_validity.py
index 68fc9c70..07d349c6 100644
--- a/core/src/apps/management/recovery_device/word_validity.py
+++ b/core/src/apps/management/recovery_device/word_validity.py
@@ -1,23 +1,35 @@
 from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
+    from typing import Awaitable, Callable
+
     from trezor.enums import BackupType
 
 
 class WordValidityResult(Exception):
-    pass
+    def __init__(self, show_error: Callable[[], Awaitable[None]]) -> None:
+        self.show_error = show_error
 
 
 class IdentifierMismatch(WordValidityResult):
-    pass
+    def __init__(self) -> None:
+        from .layout import show_identifier_mismatch
+
+        super().__init__(show_identifier_mismatch)
 
 
 class AlreadyAdded(WordValidityResult):
-    pass
+    def __init__(self) -> None:
+        from .layout import show_already_added
+
+        super().__init__(show_already_added)
 
 
 class ThresholdReached(WordValidityResult):
-    pass
+    def __init__(self) -> None:
+        from .layout import show_group_threshold
+
+        super().__init__(show_group_threshold)
 
 
 def check(backup_type: BackupType | None, partial_mnemonic: list[str]) -> None: