Merge branch 'saved-queries': saved queries in a file of their own

Items 23 and 82. Saved queries move out of the [queries] INI section into
~/.config/qtmaildir/queries.json, gaining the three things the INI could not
express: an order, a pinned flag, and a per-query account scope. They can now be
created, edited, reordered, unpinned and deleted from the UI rather than only by
hand-editing a config file.

The INI could not carry order at all: QSettings reads a section through
childKeys(), which sorts alphabetically and never follows the file, so the
buttons could not be arranged. Migration reads the old section once, marks every
entry pinned so nothing moves on the first launch, and leaves the config file
byte-identical, since rewriting it with QSettings would drop the user's comments
and key order.

Sent stops being a hardcoded button and becomes an ordinary entry carrying
"generated": "sent". Its query is still composed from the accounts every time
it runs, so correcting a folder name still needs no edit here, but the row now
follows one rule instead of having one member the user could not move, rename or
remove.

Item 82 was found by hand-testing item 23 and fixed on the same branch: saving
worked and nothing else did, so a saved query could be created and never
changed. It also uncovered a defect that predated it, where rebuilding the row
with deleteLater() left the stale row answering findChild(), which was already
reachable from the save path.

Hand-tested throughout: the migration against the real config, saving, unpinning,
deleting, reordering, the read-only query field on a generated entry, and an
unpin surviving a restart.

1 files changed, 54 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e867f02..5b14938 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,60 @@ point at which they are stable.
 
 ## [Unreleased]
 
+### Added
+
+- A **Save query** button beside the query bar, also on the Edit menu and bound
+  to `Ctrl+S`, keeps the query in the bar as a saved query: naming it,
+  optionally scoping it to one account, and choosing whether it appears as a
+  button or in a menu. Saved queries no longer have to be added by
+  hand-editing the config file (item 23).
+- Saved queries live in `~/.config/qtmaildir/queries.json`, which carries their
+  **order**, a `pinned` flag and an optional account scope. The order in the
+  file is the order the buttons appear in, so rearranging them is a matter of
+  moving lines.
+- **Sent is a saved query now**, carrying `"generated": "sent"` instead of a
+  stored query. It is still composed from your accounts' `sent` keys every time
+  you click it, so correcting a folder name still updates it with no edit, but
+  it can now be reordered, renamed, unpinned or deleted like any other entry
+  rather than being a fixed button you did not own.
+
+- **Right-click a saved query** to edit, pin, unpin or delete it. A saved query
+  could previously be created and never changed: the only route to adjusting one
+  field was to retype the whole query under the same name, and there was no way
+  to delete one at all short of editing the file (item 82). Deleting asks first,
+  since it writes your config and is not undoable.
+
+### Changed
+
+- Saved queries have a **row of their own** beneath the query bar rather than
+  sharing it, and the unpinned ones sit behind a **More queries** menu, so the
+  query field is no longer squeezed by a long list of buttons.
+- Saved-query buttons follow the file's order instead of appearing
+  alphabetically.
+- The Sent button is no longer hardcoded beside the saved queries, so the whole
+  row now follows one rule instead of having one member that behaved
+  differently from its neighbours.
+
+### Upgrading
+
+Saved queries move out of the `[queries]` section of `qtmaildir.conf` and into
+`~/.config/qtmaildir/queries.json`. **The first launch migrates them for you**:
+the section is read, the JSON file is written from it, and every entry is
+marked pinned so your buttons stay where they were. Sent is appended as a
+`generated` entry, where its button already sat, provided an account configures
+a sent folder.
+
+Your config file is left byte-for-byte alone. The old `[queries]` section stays
+in it, ignored from then on, and can be deleted by hand whenever you like. It is
+not removed automatically because rewriting the file would discard your comments
+and reorder your keys.
+
+One behaviour changes with the move. Buttons used to appear in alphabetical
+order and now follow the file. If `[general] startup_query` names a query that
+does not exist, the fallback is likewise the first query in the file rather than
+the alphabetically first one, so a config that relied on that fallback may open
+on a different query than before.
+
 ## [0.17.0] - 2026-08-13
 
 A rule is built from rows now instead of typed into four free-text fields: