Abandon recurring occurrences superseded by their next iteration

A weekly task not done before the next one lands is stale, not still
owed. The scheduler already created the successor regardless of
completion (deliberately, so skipping one doesn't stall the series), but
nothing retired the occurrence it replaced -- so every skipped occurrence
stayed open forever as a permanent overdue item. Live: "Bills" and
"Bones's meds" each sat in the list twice.

AdvanceDueRecurringTasks now marks the superseded occurrence abandoned
when it creates the successor. A separate flag rather than `completed`,
because these were never done and crediting them would corrupt
completion history. All four open-task queries filter it out; migration
030 adds the column and backfills the occurrences already superseded
(exactly the 2 above, verified against production before deploying).

Supersedes the earlier view-level collapse (10f9fcd, reverted in
96518ad): that kept the *earliest* open instance, which is backwards --
the stale one should go and the current one stand -- and it only hid the
row in the flat list while leaving it overdue in the timeline and widget,
which is where it was actually being seen.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018AwnALZL6bD4VBtATDVv3B

1 files changed, 23 insertions, 0 deletions

diff --git a/migrations/030_abandon_stale_recurrences.sql b/migrations/030_abandon_stale_recurrences.sql
new file mode 100644
index 0000000..f8ec225
--- /dev/null
+++ b/migrations/030_abandon_stale_recurrences.sql
@@ -0,0 +1,23 @@
+-- A recurring task that wasn't done before its next iteration arrived is stale,
+-- not still-owed: the next one supersedes it. Without a way to record that, every
+-- skipped occurrence stayed open forever and piled up as permanent overdue items
+-- (found live: "Bills" and "Bones's meds" each sitting in the list twice, an
+-- unfinished instance alongside its already-generated successor).
+--
+-- Deliberately a separate flag rather than reusing `completed`: these were never
+-- done, and marking them completed would falsely credit them and pollute
+-- completion history.
+ALTER TABLE native_tasks ADD COLUMN abandoned BOOLEAN DEFAULT 0;
+
+-- Backfill: any uncompleted recurring instance that already has a later sibling
+-- in its series was superseded before this flag existed.
+UPDATE native_tasks
+SET abandoned = 1
+WHERE completed = 0
+  AND recurrence_series_id != ''
+  AND due_date IS NOT NULL
+  AND EXISTS (
+    SELECT 1 FROM native_tasks later
+    WHERE later.recurrence_series_id = native_tasks.recurrence_series_id
+      AND later.due_date > native_tasks.due_date
+  );