BAL - Bitcoin After Life Electrum plugin (v0.2.8)

Behavior-preserving refactor of the original BAL plugin with clean separation
of business logic from the PyQt GUI.

Layout:
  bal/core/   GUI-free logic (util, plugin_base, heirs, will, willexecutors)
  bal/gui/qt/ PyQt6 presentation (theme, common, widgets, calendar, dialogs,
              lists, window, plugin)
  bal/qt.py   Qt entry-point shim (works as internal and external zip plugin)
  bal/manifest.json  standard-conforming metadata

Tooling:
  build_zip.py            deterministic, zipimport-friendly archive builder
  tests/smoke_test.py     imports + behavior regression test
  tests/external_zip_test.py  reproduces Electrum's external-zip loading

Targets Electrum 4.7.2 + PyQt6. Logic kept byte-identical where possible.

bal/gui/qt/calendar.py

@@ -0,0 +1,80 @@
+"""
+bal.gui.qt.calendar
+===================
+
+iCalendar (.ics) generation and "open with default calendar app" helper.
+
+When a will is built, the plugin can create a calendar event reminding the user
+to "check in" before the locktime expires.  This module turns the event data
+into an RFC-5545 .ics file and opens it with the OS default application.
+"""
+
+from .common import *
+from .common import _, _logger  # underscore names are not re-exported by "import *"
+
+class BalCalendar:
+    @staticmethod
+    def write_temp_ics(content):
+        fd, path = tempfile.mkstemp(prefix="event_", suffix=".ics")
+        with os.fdopen(fd, "wb") as f:
+            f.write(content.encode("utf-8"))
+        return path
+
+    @staticmethod
+    def open_with_default_app(calendar_app, path):
+        _logger.debug("opening calendar app")
+        try:
+            subprocess.check_call([calendar_app, path])
+            return True
+        except Exception as e:
+            _logger.error(f"starting calendar app {e}")
+            return False
+
+
+    @staticmethod
+    def format_time(time):
+        return time.astimezone(timezone.utc).strftime("%Y%m%dT%H%M%SZ")
+        #return time.astimezone(timezone.utc).strftime("%Y%m%d")
+
+    @staticmethod
+    def ical_escape(text: str) -> str:
+        # escape per RFC5545: backslash, ; , newlines
+        text = text.encode("utf-8")
+        text = (
+            text.replace(b"\\", b"\\\\")
+            .replace(b";", b"\\;")
+            .replace(b",", b"\\,")
+        )
+        out =""
+        temp=text.split(b"\r\n")
+        for s in temp:
+            encoded= s
+            cut =0
+            while len(encoded) >75:
+                cut+=5
+                encoded=f"{s[:len(s)-cut]}"
+                if encoded[-1]==b"\\" and encoded[-2]!=b"\\\\":
+                    cut += 1
+                encoded=f"{s[:len(s)-cut]}"
+                encoded=f"{encoded}...\r\n".encode("utf-8")
+            if cut>0:
+                out+=str(f"{s[:len(s)-cut].decode()}...\r\n")
+            else:
+                out+=str(f"{s.decode()}\r\n")
+
+        return out[:-2]
+
+    @staticmethod
+    def fold_ical_line(line: str, limit: int = 75) -> str:
+        # ritorna linee separate da CRLF e folding con spazio iniziale sulle righe successive
+        encoded = line.encode("utf-8")
+        parts = []
+        while len(encoded) > limit:
+            # taglia senza spezzare byte UTF-8
+            cut = limit
+            while (encoded[cut] & 0xC0) == 0x80:  # byte di continuazione UTF-8
+                cut -= 1
+            parts.append(encoded[:cut].decode("utf-8"))
+            encoded = encoded[cut:]
+        parts.append(encoded.decode("utf-8"))
+        return "\r\n ".join(parts)