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, 70 insertions, 14 deletions

diff --git a/README.md b/README.md
index 0921791..9148923 100644
--- a/README.md
+++ b/README.md
@@ -106,7 +106,7 @@ identity.
 ; point: once you zoom with Ctrl+wheel or Ctrl+/Ctrl-, that is remembered
 ; separately and this value no longer applies.
 ; message_zoom = 1.0
-; Optional. Which [queries] entry to open at startup, by name. Defaults to
+; Optional. Which saved query to open at startup, by name. Defaults to
 ; Unread. Falls back to the first saved query if no query by this name
 ; exists, and warns if you named one explicitly.
 ; startup_query = Unread
@@ -191,11 +191,6 @@ shopping = #3366cc         ; also colours shopping/amazon, shopping/nike, ...
 shopping/amazon = #ff9900  ; ... unless the exact tag overrides it
 work = #cc4444
 
-[queries]
-Inbox = tag:inbox
-Unread = tag:unread
-Important = tag:flagged
-
 [keys]
 Ctrl+E = archive
 Ctrl+D = delete
@@ -203,14 +198,73 @@ j = next_thread
 k = prev_thread
 ```
 
-Saved-query buttons appear in alphabetical order rather than file order:
-QSettings returns keys sorted, and preserving file order would mean
-hand-rolling an INI parser. Which query opens at startup is therefore a
-separate setting, `[general] startup_query`, rather than "the first one".
+### Saved queries
+
+Saved queries live in `~/.config/qtmaildir/queries.json`, not in the config
+file. They are written by the **Save query** action (`Ctrl+S`), which names the
+query in the bar, optionally scopes it to one account, and chooses whether it
+gets a button:
+
+```json
+{
+  "version": 1,
+  "queries": [
+    { "name": "Inbox",  "query": "tag:inbox",  "pinned": true },
+    { "name": "Unread", "query": "tag:unread", "pinned": true },
+    { "name": "Billing", "query": "from:billing", "account": "work" }
+  ]
+}
+```
+
+The order in the file is the order the buttons appear in, so rearranging them
+is a matter of moving lines. `pinned` decides between a button and the **More
+queries** menu, which keeps the row usable once you have more than a handful.
+`account` names an `[account.<key>]` section and scopes the query to it, the
+same as choosing that account in the dropdown; leave it out for a query that
+spans every account.
+
+**Sent is an entry like any other**, and the one that carries `generated`
+instead of `query`:
+
+```json
+{ "name": "Sent", "generated": "sent", "pinned": true }
+```
 
-The button text is the key you write here, so these names are yours to
-choose. `Important = tag:flagged` and `Flagged = tag:flagged` run the same
-query and differ only in what the button says.
+A generated query is composed from your accounts every time you click it,
+rather than stored. That is why Sent has no `query` of its own: it is built
+from every account's `sent` key, so adding an account or correcting a folder
+name updates the button with no edit here. A stored copy of the same string
+would quietly go on naming the old folder.
+
+Being an ordinary entry, it can be reordered, renamed, unpinned or deleted like
+the rest. Renaming it to `Posta inviata` changes only the label. `sent` is the
+only generator today, and it is skipped entirely when no account configures a
+sent folder, rather than offering a button that finds nothing.
+
+The name is what the button says, so `Important` and `Flagged` can run the same
+query and differ only in the label.
+
+**Right-click a saved query** (a button, or its entry in the menu) to edit it,
+move it between the row and the menu, or delete it. Deleting asks first: it
+rewrites this file and there is no undo for it. Editing a generated entry shows
+its composed query read-only, since that one is built from your accounts rather
+than stored.
+
+**Upgrading from 0.17.0 or earlier.** Saved queries used to live in a
+`[queries]` section of `qtmaildir.conf`. The first launch after upgrading reads
+that section, writes `queries.json` from it, and marks every entry pinned so
+your buttons stay where they were. Sent is added as a `generated` entry at the
+end, where its button already sat, provided an account configures a sent
+folder. Your config file is not modified: the old `[queries]` section is left
+exactly as it is, ignored from then on, and you can delete it by hand whenever
+you like. The reason it is not removed for you is that rewriting the file would
+drop your comments and reorder your keys.
+
+One behaviour changes with the move. Buttons used to appear in alphabetical
+order, because the INI backend returns keys sorted and preserving file order
+would have meant hand-rolling a parser. They now follow the file. If
+`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.
 
 ### Sent mail
 
@@ -253,7 +307,8 @@ behaves like any other query, threads and all.
 ## The query bar
 
 The bar at the top takes a notmuch query and shows the matching threads.
-Saved queries from `[queries]` sit beside it as buttons.
+Saved queries sit on their own row beneath it: the pinned ones as buttons, the
+rest behind **More queries**. `Ctrl+S` keeps the current query as a new one.
 
 Completion helps with the syntax rather than replacing it. `Ctrl+Space`
 opens the popup, and ordinary typing keeps it up to date. Candidates carry a
@@ -478,6 +533,7 @@ Defaults, all rebindable through `[keys]`:
 | `Ctrl+I` | `flag` | Mark important (adds `flagged`) |
 | `Ctrl+L` | `focus_query` | Focus and select the query bar |
 | `Ctrl+Space` | `complete_query` | Focus the query bar and offer completions |
+| `Ctrl+S` | `save_query` | Keep the current query as a saved query |
 | `Ctrl+H` | `toggle_html` | Switch the thread between HTML and plain text |
 | `Ctrl+M` | `load_remote` | Load remote images for the current thread |
 | `Ctrl+T` | `edit_tags` | Add or remove any tag on the selected threads |