build: add lib-recur to :app, and a dmfs v23 fixture for the import

The own store expands recurrences itself, so lib-recur is a direct
dependency now rather than something :provider drags in. Still pinned at
0.12.2 — 0.16.0 removed RecurrenceSet.

scripts/make_import_fixture.py writes the tasks.db the one-shot import
will be tested against: the provider's DATABASE_VERSION 23 schema, seeded
with the cases the import has to get right (a task with no UID, a deleted
row, a recurring series, an all-day task, a subtask, an alarm property,
and a list under a real CalDAV account). The provider is being deleted, so
a fixture is the only way to keep testing against the schema it wrote.

app/build.gradle.kts

@@ -169,6 +169,12 @@ dependencies {
     implementation(libs.androidx.navigation.compose)
     ksp(libs.hilt.compiler)
 
+    // RFC 5545 recurrence expansion, in-process. Pulled in directly rather than
+    // through :provider: the own store expands occurrences itself. Pinned at
+    // 0.12.2 — 0.16.0 removed RecurrenceSet. rfc5545-datetime comes with it and
+    // is part of its API surface, so it isn't declared separately.
+    implementation(libs.dmfs.lib.recur)
+
     implementation(libs.androidx.room.runtime)
     implementation(libs.androidx.room.ktx)
     ksp(libs.androidx.room.compiler)

scripts/make_import_fixture.py

@@ -0,0 +1,142 @@
+#!/usr/bin/env python3
+"""Build the dmfs `tasks.db` fixture the one-shot import is tested against.
+
+The provider is being deleted (docs/OWN-STORE.md phase 5), so the import cannot
+keep a real v0.3.x database around by asking the provider to create one. This
+writes the schema the provider's TaskDatabaseHelper produces at DATABASE_VERSION
+23 — tables `Lists`, `Tasks`, `Properties` only, which are the three the import
+reads — and seeds a spread that covers what the import has to get right.
+
+Regenerate with:  python3 scripts/make_import_fixture.py
+"""
+
+from __future__ import annotations
+
+import os
+import sqlite3
+import sys
+
+OUT = os.path.join(
+    os.path.dirname(os.path.dirname(os.path.abspath(__file__))),
+    "app/src/androidTest/assets/tasks-v23.db",
+)
+
+DDL = [
+    """CREATE TABLE Lists (
+        _id INTEGER PRIMARY KEY AUTOINCREMENT,
+        account_name TEXT, account_type TEXT, list_name TEXT, list_color INTEGER,
+        list_access_level INTEGER, visible INTEGER, sync_enabled INTEGER,
+        list_owner TEXT, _dirty INTEGER DEFAULT 0, _sync_id TEXT,
+        sync_version TEXT, sync1 TEXT, sync2 TEXT, sync3 TEXT, sync4 TEXT,
+        sync5 TEXT, sync6 TEXT, sync7 TEXT, sync8 TEXT)""",
+    """CREATE TABLE Tasks (
+        _id INTEGER PRIMARY KEY AUTOINCREMENT, version INTEGER DEFAULT 0,
+        list_id INTEGER NOT NULL, title TEXT, location TEXT, geo TEXT,
+        description TEXT, url TEXT, organizer TEXT, priority INTEGER,
+        task_color INTEGER, class INTEGER, completed INTEGER,
+        completed_is_allday INTEGER, percent_complete INTEGER,
+        status INTEGER DEFAULT 0, is_new INTEGER, is_closed INTEGER,
+        dtstart INTEGER, created INTEGER, last_modified INTEGER,
+        is_allday INTEGER, tz TEXT, due INTEGER, duration TEXT, rdate TEXT,
+        exdate TEXT, rrule TEXT, parent_id INTEGER, sorting TEXT,
+        has_alarms INTEGER, has_properties INTEGER, pinned INTEGER,
+        original_instance_sync_id TEXT, original_instance_id INTEGER,
+        original_instance_time INTEGER, original_instance_allday INTEGER,
+        _dirty INTEGER DEFAULT 1, _deleted INTEGER DEFAULT 0, _sync_id TEXT,
+        _uid TEXT, sync_version TEXT, sync1 TEXT, sync2 TEXT, sync3 TEXT,
+        sync4 TEXT, sync5 TEXT, sync6 TEXT, sync7 TEXT, sync8 TEXT)""",
+    """CREATE TABLE Properties (
+        property_id INTEGER PRIMARY KEY AUTOINCREMENT, task_id INTEGER,
+        mimetype INTEGER, prop_version INTEGER,
+        data0 TEXT, data1 TEXT, data2 TEXT, data3 TEXT, data4 TEXT, data5 TEXT,
+        data6 TEXT, data7 TEXT, data8 TEXT, data9 TEXT, data10 TEXT,
+        data11 TEXT, data12 TEXT, data13 TEXT, data14 TEXT, data15 TEXT,
+        prop_sync1 TEXT, prop_sync2 TEXT, prop_sync3 TEXT, prop_sync4 TEXT,
+        prop_sync5 TEXT, prop_sync6 TEXT, prop_sync7 TEXT, prop_sync8 TEXT)""",
+]
+
+LOCAL = ("Local", "org.dmfs.account.LOCAL")
+CALDAV = ("me@example.org", "bitfire.at.davdroid")
+ALARM_MIMETYPE = "vnd.android.cursor.item/alarm"
+
+# 2026-01-15T09:00:00Z, and a day in millis.
+T0 = 1_768_467_600_000
+DAY = 86_400_000
+
+
+def seed(db: sqlite3.Connection) -> None:
+    lists = db.executemany(
+        "INSERT INTO Lists (_id, account_name, account_type, list_name, list_color,"
+        " visible, sync_enabled, list_owner) VALUES (?,?,?,?,?,?,?,?)",
+        [
+            (1, *LOCAL, "Personal", 0xFF7A5C6B, 1, 1, None),
+            (2, *LOCAL, "Hidden list", 0xFF445566, 0, 1, None),
+            # An external account inside our own authority: only reachable if the
+            # user pointed DAVx5 at us. Imported as a local list, UID preserved.
+            (3, *CALDAV, "Work", 0xFF2244AA, 1, 1, "Me"),
+        ],
+    )
+    del lists
+
+    def task(**kw):
+        cols = ", ".join(kw)
+        marks = ", ".join("?" * len(kw))
+        db.execute(f"INSERT INTO Tasks ({cols}) VALUES ({marks})", tuple(kw.values()))
+
+    task(_id=1, list_id=1, title="Buy milk", due=T0 + DAY, status=0,
+         _uid="a1b2c3d4-0000-4000-8000-000000000001", created=T0, last_modified=T0)
+    # No UID: the import mints one.
+    task(_id=2, list_id=1, title="Call the dentist", due=T0 + 2 * DAY, status=1,
+         percent_complete=40, created=T0, last_modified=T0)
+    task(_id=3, list_id=1, title="Gather receipts", parent_id=1, status=0,
+         _uid="a1b2c3d4-0000-4000-8000-000000000003", created=T0, last_modified=T0)
+    task(_id=4, list_id=1, title="Renew domain", status=2, percent_complete=100,
+         completed=T0 - DAY, is_closed=1,
+         _uid="a1b2c3d4-0000-4000-8000-000000000004", created=T0, last_modified=T0)
+    task(_id=5, list_id=1, title="Water the plants", dtstart=T0, due=T0 + 3600_000,
+         rrule="FREQ=WEEKLY;BYDAY=MO,TH", tz="Europe/Berlin",
+         _uid="a1b2c3d4-0000-4000-8000-000000000005", created=T0, last_modified=T0)
+    task(_id=6, list_id=1, title="Team offsite", dtstart=T0 - T0 % DAY,
+         due=T0 - T0 % DAY + DAY, is_allday=1,
+         _uid="a1b2c3d4-0000-4000-8000-000000000006", created=T0, last_modified=T0)
+    # Deleted-but-unsynced: gone as far as the user is concerned, so not imported.
+    task(_id=7, list_id=1, title="Cancelled thing", _deleted=1,
+         _uid="a1b2c3d4-0000-4000-8000-000000000007", created=T0, last_modified=T0)
+    task(_id=8, list_id=2, title="Task in a hidden list", status=0,
+         _uid="a1b2c3d4-0000-4000-8000-000000000008", created=T0, last_modified=T0)
+    task(_id=9, list_id=3, title="Ship the release", due=T0 + 5 * DAY, status=0,
+         _uid="a1b2c3d4-0000-4000-8000-000000000009", created=T0, last_modified=T0,
+         _sync_id="https://dav.example.org/tasks/9.ics")
+
+    db.executemany(
+        "INSERT INTO Properties (property_id, task_id, mimetype, data0, data1, data2, data3)"
+        " VALUES (?,?,?,?,?,?,?)",
+        [
+            # data0 minutes before, data1 reference (1 = DUE), data3 alarm type.
+            (1, 1, ALARM_MIMETYPE, "30", "1", None, "1"),
+            (2, 9, ALARM_MIMETYPE, "1440", "1", "Ship it", "1"),
+            # A non-alarm property the import must skip.
+            (3, 1, "vnd.android.cursor.item/category", "Errands", None, None, None),
+        ],
+    )
+
+
+def main() -> int:
+    os.makedirs(os.path.dirname(OUT), exist_ok=True)
+    if os.path.exists(OUT):
+        os.remove(OUT)
+    db = sqlite3.connect(OUT)
+    try:
+        for statement in DDL:
+            db.execute(statement)
+        db.execute("PRAGMA user_version = 23")
+        seed(db)
+        db.commit()
+    finally:
+        db.close()
+    print(f"wrote {OUT}")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())