docs: close item 36, narrow item 66 with a negative result

Item 36's section moves to the closed file and its three traps go into
CLAUDE.md, which is where they will be read: the worker is unreachable
by findChild, rowCount on an unexpanded thread row is 0 by design, and
currentThreadId reports intent rather than content.

The claim that this class of bug cannot be reproduced in test_mainwindow
is now false, so it is corrected rather than left standing beside its
replacement. One in-test reference to item 36 as a permanent limitation
is reworded: bare-window cases still have no worker, but that is now a
choice per case rather than a property of the binary.

Item 66 stays open with the simple case ruled out. The negative result
sharpens this entry's own candidate rather than contradicting it: the
test drives setCurrentIndex, which updates the selection model
synchronously, while the suspect guard turns on a real click not having
done so yet. Two cheaper conditions are named as still unexcluded.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

2 files changed, 67 insertions, 44 deletions

diff --git a/docs/superpowers/plans/2026-08-03-post-0.1.0-usability-closed.md b/docs/superpowers/plans/2026-08-03-post-0.1.0-usability-closed.md
index 221b3b2..ed88693 100644
--- a/docs/superpowers/plans/2026-08-03-post-0.1.0-usability-closed.md
+++ b/docs/superpowers/plans/2026-08-03-post-0.1.0-usability-closed.md
@@ -4893,3 +4893,47 @@ a keybinding and nothing is broken.
 **The consequence for item 36.** That item could not add fixture-backed tests
 while a malformed config could hang the constructor. It can now, which is why
 84 was done first.
+
+## 36. `test_mainwindow` cannot reach the worker
+
+**Done 2026-08-14, unreleased.** See
+`specs/2026-08-14-mainwindow-worker-fixture-design.md`.
+
+**Observed:** twice in one session (0.8.0), a defect could not be given a
+regression test because `MainWindow` in tests had no notmuch database, so its
+`NotmuchWorker` never emitted `threadLoaded`. One of those, the guard in
+`onThreadLoaded()` against a queued load repainting a pane a multi-row selection
+had just blanked, is now covered: the reproduction written here fails when that
+handler is disabled.
+
+**Shipped as `WorkerBackedWindow` in `test_mainwindow.cpp`, opt-in per test,
+with NO production change.** `wireWorker()` already built the worker from
+`m_config.notmuchConfig()`, an ordinary config key, so a written
+`qtmaildir.conf` pointing at the fixture exercises the shipping path. The entry
+had read as bigger than it was since 2026-08-04 because it assumed a hook was
+needed.
+
+**Three traps found while writing it, each of which had made an earlier version
+of the test worthless. All three are worth knowing before touching this area.**
+
+The worker is **unreachable by `findChild`**. `wireWorker()` creates it
+parentless and immediately moves it to its own thread, so it is not in the
+window's object hierarchy. The tests wait with `QTRY_VERIFY_WITH_TIMEOUT` on
+observable state instead, which is the better assertion anyway.
+
+**`rowCount()` on a thread row is 0 until the thread is expanded**, because
+children are populated by the expansion. `hasChildren()` is the correct
+pre-expansion question, falling back to `summary.totalCount > 1`, and it is also
+what proves two messages threaded rather than arriving as two rows. An assertion
+on `rowCount` fails against correct code.
+
+**`currentThreadId()` reports intent, not content.** It is assigned
+synchronously in the selection handler at `src/mainwindow.cpp:2387`, before any
+worker round-trip, so a test asserting on it passed with `onThreadLoaded()`
+disabled entirely. `MessageView::showingPlaceholder()` is what the user sees.
+The test asserts the pane IS blank before the click, so the assertion after it
+means something.
+
+**Item 66 did not reproduce**, which is recorded in that item rather than
+worked around here. The test was not widened until it failed; the negative
+result and what it narrows to are in item 66's own entry.
diff --git a/docs/superpowers/plans/2026-08-03-post-0.1.0-usability.md b/docs/superpowers/plans/2026-08-03-post-0.1.0-usability.md
index 9240ad6..2594890 100644
--- a/docs/superpowers/plans/2026-08-03-post-0.1.0-usability.md
+++ b/docs/superpowers/plans/2026-08-03-post-0.1.0-usability.md
@@ -100,7 +100,7 @@ taking that too literally.
 | 33 | Status bar messages never expire | feedback | S | **done** |
 | 34 | No overview of the Maildir itself | information | M | **done** |
 | 35 | No refresh of the thread list after a sync | workflow | M | **done** 2026-08-10; the list now follows a sync on its own |
-| 36 | `test_mainwindow` cannot reach the worker | testing | S-M | open, specced 2026-08-14; see `specs/2026-08-14-mainwindow-worker-fixture-design.md`. No longer on demand: item 66 needs it. Smaller than it reads, `wireWorker()` already builds the worker from a config key |
+| 36 | `test_mainwindow` cannot reach the worker | testing | S-M | **done** 2026-08-14, unreleased; see `specs/2026-08-14-mainwindow-worker-fixture-design.md`. `WorkerBackedWindow`, opt-in per test, no production change. Its first use ruled out the simple case of item 66 |
 | 37 | The worker stalls on a tag edit made during a background sync | correctness | S | **done** |
 | 38 | `test_mainwindow` fails when a real sync holds the lock | testing | XS | **done** |
 | 39 | Thread list cannot be sorted by clicking a column header | workflow | S | **dropped** 2026-08-10; the card list has no column headers to click, and 0.13.0 shipped a sort dropdown instead |
@@ -130,7 +130,7 @@ taking that too literally.
 | 63 | No way to see sent mail, and no filter for it | workflow | M | **done** 2026-08-11; see `specs/2026-08-11-sent-mail-design.md` |
 | 64 | The Sync button carries a mailbox icon, not a refresh one | presentation | XS | **done** 2026-08-11 |
 | 65 | No full code review and optimization pass | correctness | ? | open, unspecified |
-| 66 | Selecting a thread root leaves the message pane blank until a reply has been selected | defect | S | open; needs a reproduction before a fix |
+| 66 | Selecting a thread root leaves the message pane blank until a reply has been selected | defect | S | open; the simple case is RULED OUT, measured 2026-08-14 with the item 36 fixture. Needs a condition nobody has named yet, see the section |
 | 67 | The placeholder pane counts unread, flagged and inbox, but not sent or drafts | information | XS | **done** 2026-08-11, shipped in 0.15.0 |
 | 68 | A forwarded subject gets no `passed` tag | workflow | S | open; no subject rule exists, measured 2026-08-11. Decision needed: display mark (XS) or write the flag (S, syncs out) |
 | 69 | `passed` and `replied` read as words where every other state is a glyph | presentation | S | **done** 2026-08-11, inside item 70 |
@@ -214,42 +214,6 @@ literal, the descriptions are prose.
 **Verification:** run `lupdate` and read the generated `.ts`. A string that
 does not appear there is not translatable, whatever the source looks like.
 
-## 36. `test_mainwindow` cannot reach the worker
-
-**Observed:** twice in one session (0.8.0), a defect could not be given a
-regression test because `MainWindow` in tests has no notmuch database, so its
-`NotmuchWorker` never emits `threadLoaded`. Both were verified by hand and by a
-standalone model instead:
-
-- A queued `threadLoaded` repainting a pane that a multi-row selection had just
-  blanked. The fix guards `onThreadLoaded()`, and that guard is untested: the
-  test passes with it reverted.
-- A local sync reporting itself as a background one. Staging it needs
-  `MailSync::isRunning()` true at one transition and false at the next, which
-  needs a configured sync command and a live child process. That was tried and
-  abandoned: it left a process running for the length of the suite and popped a
-  dialog on the user's screen.
-
-**The machinery already exists and is not the gap.** `tests/notmuchfixture.h`
-builds a throwaway Maildir in a `QTemporaryDir`, runs `notmuch new` with
-`NOTMUCH_CONFIG` scoped to the test process, and `addMessage()` takes
-message-id, subject, from, date, body, unread and in-reply-to, so threads come
-from real `In-Reply-To` chains. `test_notmuchworker` uses it. `test_mainwindow`
-does not.
-
-**Explicitly rejected: a corpus built from the user's real mail.** Considered
-and declined 2026-08-04. The global rule against personal data in fixtures
-forbids it, git hooks enforce it, and this repository is public. Scrubbing is
-also the fragile path: one surviving `In-Reply-To` or `References` header names a
-real correspondent, and a scrubbed message no longer demonstrates what the real
-one did. Where a real message exposes a parser bug, hand-write a minimal `.eml`
-reproducing its **shape**, as `truncated.eml` and `hostile_filename.eml` already
-do.
-
-**Specced 2026-08-14: read
-`specs/2026-08-14-mainwindow-worker-fixture-design.md` rather than planning from
-here.**
-
 **No longer on demand.** The entry said to do this when a defect needs it, not
 before (user, 2026-08-04). Item 66 needs it now, so the deliverable is a RED
 reproduction of that defect, not fixture wiring on its own. Fixing 66 is
@@ -263,10 +227,6 @@ writes a `qtmaildir.conf` pointing at the fixture gets a real worker through the
 shipping path with nothing in `src/` changed. Mind the `[general]` prefix trap
 when writing that file.
 
-**Constraint:** every existing `test_mainwindow` case constructs a bare
-`MainWindow` and must keep working. The fixture is opt-in per test, not a
-suite-wide `initTestCase`, or every case pays for a `notmuch new`.
-
 ## 40. No live filter over the current view
 
 **Observed (user, 2026-08-05):** "search in current view", spelled out as two
@@ -360,8 +320,27 @@ load and `onSelectionChanged` only reloads when the row CHANGED
 kind of plausible cause the project has been burned by twice; instrument the
 running application and watch the order of `currentRowChanged`,
 `selectionChanged` and the worker reply for one first click on a cold view.
-`test_mainwindow` cannot reproduce it: it has no worker and never fires
-`threadLoaded`.
+
+**Ruled out 2026-08-14: the simple case does not reproduce.** Item 36 shipped
+the fixture this entry said was missing, and
+`selectingAThreadRootShowsItInTheMessagePane` in `test_mainwindow` now builds a
+real database, runs a real query and selects an unexpanded thread root with a
+real `threadLoaded` arriving. The pane renders. The test is mutation-confirmed
+to fail when `onThreadLoaded()` is disabled, so it is a probe with teeth rather
+than a green that proves nothing.
+
+**What that leaves, and it sharpens this entry's own candidate.** The test uses
+`setCurrentIndex()`, which updates the selection model SYNCHRONOUSLY. A real
+mouse click does not, and the guard at `src/mainwindow.cpp:1804` returns without
+loading when the index is not yet selected. So the negative result is consistent
+with the candidate above rather than against it: it says the defect is in the
+CLICK path, not in the load path. Reproducing it needs `QTest::mouseClick` on
+the viewport at the row's `visualRect`, not a programmatic selection.
+
+Two other conditions remain unexcluded and are cheaper to try than a click
+harness: a thread of more than two messages, and a cold page cache, which item
+74 measures as seconds on this machine and which is exactly the window in which
+an ordering fault would show.
 
 **Constraints:** the mark-read guard at 1804 must survive whatever is done, it is
 item 35b's fix and removing it re-opens marking mail read without the user having