i18n phases 1+2: BAL translation layer and translatable texts

Phase 1: new bal/i18n.py, BAL's own gettext layer (domain "bal", catalogs
read with plugin.read_file()). _() asks Electrum's catalog first, then
BAL's, then returns the English source. The Qt plugin loads the catalog of
Electrum's GUI language at start-up; the CLI stays English.

Phase 2: every user-visible GUI text is now a whole, extractable sentence
(Ruff INT rules enabled). Class-level texts are marked with N_() and
translated when shown. Stored data stays language-neutral: the status
history is written in English and translated for display, the calendar
defaults follow the GUI language, and the history label and wallet labels
are never translated because BAL uses them to recognise its transactions.

No visible change apart from the double colon fixed in the will detail.
See CHANGELOG entries 58 and 59 and PLAN_I18N.md.

bal/core/will.py

@@ -29,7 +29,6 @@ The status flags themselves (the source of truth) stay here; only the mapping
 from datetime import datetime, timezone
 
 from electrum.address_synchronizer import TX_HEIGHT_FUTURE, TX_HEIGHT_LOCAL
-from electrum.i18n import _
 from electrum.logging import Logger, get_logger
 from electrum.transaction import (
     PartialTransaction,
@@ -44,6 +43,7 @@ from electrum.util import (
     bfh,
 )
 
+from ..i18n import N_, _
 from .heirs import WillExecutorFeeTooHighException
 from .util import Util, copy_structure
 from .willexecutors import Willexecutors
@@ -1273,6 +1273,34 @@ class Will:
 
 
 
+def format_status_history(status: str) -> str:
+    """Return the saved status history of a will item in the GUI language.
+
+    ``WillItem.status`` is a dot-separated history such as
+    ``".Signed.Pushed.NOT Valid"``. It is stored in English (see
+    ``WillItem.set_status``) and translated only here, for display. A token
+    that is not a known English label is shown unchanged: this keeps working
+    the histories written by older versions, which stored the label already
+    translated (for example ``"Firmato"``).
+    """
+    labels = {label for label, _flag in WillItem.STATUS_DEFAULT.values()}
+    labels.update(WillItem.LEGACY_STATUS_LABELS)
+
+    def translate(token):
+        # "ERROR!!!" is glued to the end of the history when an item has no
+        # id (see WillItem.__init__): keep it, translate what comes before.
+        suffix = ""
+        if token.endswith("ERROR!!!"):
+            token, suffix = token[: -len("ERROR!!!")], "ERROR!!!"
+        if token in labels:
+            token = _(token)
+        elif token.startswith("NOT ") and token[len("NOT "):] in labels:
+            token = _("NOT {}").format(_(token[len("NOT "):]))
+        return token + suffix
+
+    return ".".join(translate(token) for token in status.split("."))
+
+
 class WillItem(Logger):
     # Default status flags for an inheritance transaction.
     # Each entry maps an internal status key to [human-readable label, default
@@ -1286,28 +1314,37 @@ class WillItem(Logger):
     #   * "UPDATED" was added: the transaction was spendable AND valid, and a new
     #     transaction replaces it while keeping the SAME locktime and SAME heirs.
     #     UPDATED keeps the VALID flag (see set_status).
+    #
+    # The labels are marked with N_() but stay English here: they are written
+    # into the saved status history (see set_status) and translated only when
+    # shown, by format_status_history().
     STATUS_DEFAULT = {
-        "ANTICIPATED": ["Anticipated", False],
-        "BROADCASTED": ["Broadcasted", False],
-        "CHECKED": ["Checked", False],
-        "CHECK_FAIL": ["Check Failed", False],
-        "COMPLETE": ["Signed", False],
-        "CONFIRMED": ["Confirmed", False],
-        "ERROR": ["Error", False],
-        "EXPIRED": ["Expired", False],
-        "EXPORTED": ["Exported", False],
-        "IMPORTED": ["Imported", False],
-        "INVALIDATED": ["Invalidated", False],
-        "MEMPOOL": ["Mempool", False],
-        "PUSH_FAIL": ["Push failed", False],
-        "PUSHED": ["Pushed", False],
-        "PARTIALLY_SIGNED": ["Partially Signed", False],
-        "REPLACED": ["Replaced", False],
-        "RESTORED": ["Restored", False],
-        "UPDATED": ["Updated", False],
-        "VALID": ["Valid", True],
+        "ANTICIPATED": [N_("Anticipated"), False],
+        "BROADCASTED": [N_("Broadcasted"), False],
+        "CHECKED": [N_("Checked"), False],
+        "CHECK_FAIL": [N_("Check Failed"), False],
+        "COMPLETE": [N_("Signed"), False],
+        "CONFIRMED": [N_("Confirmed"), False],
+        "ERROR": [N_("Error"), False],
+        "EXPIRED": [N_("Expired"), False],
+        "EXPORTED": [N_("Exported"), False],
+        "IMPORTED": [N_("Imported"), False],
+        "INVALIDATED": [N_("Invalidated"), False],
+        "MEMPOOL": [N_("Mempool"), False],
+        "PUSH_FAIL": [N_("Push failed"), False],
+        "PUSHED": [N_("Pushed"), False],
+        "PARTIALLY_SIGNED": [N_("Partially Signed"), False],
+        "REPLACED": [N_("Replaced"), False],
+        "RESTORED": [N_("Restored"), False],
+        "UPDATED": [N_("Updated"), False],
+        "VALID": [N_("Valid"), True],
     }
 
+    # Labels found in histories saved by older versions but no longer
+    # written: "New" opened every history (e.g. tests/samanta7).
+    # format_status_history() still translates them.
+    LEGACY_STATUS_LABELS = (N_("New"),)
+
     def set_status(self, status, value=True):
         """Set a status flag and apply the related side effects.
 
@@ -1341,7 +1378,11 @@ class WillItem(Logger):
         if self.STATUS[status][1] == bool(value):
             return None
 
-        self.status += "." + (("NOT " if not value else "") + _(self.STATUS[status][0]))
+        # The history is saved in the wallet, in exported files and in QR
+        # transfers, so it is always written in English: the saved data must
+        # not depend on the GUI language (older versions wrote the translated
+        # label). format_status_history() translates it when it is shown.
+        self.status += "." + (("NOT " if not value else "") + self.STATUS[status][0])
         self.STATUS[status][1] = bool(value)
         if value:
             # NOTE: ANTICIPATED and UPDATED are intentionally NOT in this list,