Merge branch 'compose-and-send': composing and sending mail

Item 123, built over 2026-08-20 to 2026-08-23 in thirteen tasks against
docs/superpowers/specs/2026-08-20-compose-and-send-design.md.

The application writes mail now. A composer window per message, markdown as
the body, drafts autosaving into the account's Maildir, and sending through a
per-account command on stdin rather than any network protocol of this
program's own. A countdown with an Undo stands between pressing Send and the
command running.

Two things came in alongside it. The notmuch auto-tagging hooks moved here
from the retiring `mailctl` project and learned that mail this application
files itself never arrived, so sent mail and drafts stop appearing in the
inbox. And the v1/v2 language is retired: semver on the user-visible surface
is the rule, and those labels described a split that composing made obsolete.

Hand tested against a fake send command rather than a real one, deliberately:
New, Reply and Forward all produce correct messages, a forwarded attachment
survives intact, and the sent copy is filed. That testing found the two
defects fixed on this branch, and both were invisible to the suite: a composer
orphaned by quitting the main window, and every sent message tagged `inbox`.

Twenty-two defects were found in the plan document's own draft code while
building it, which is why CLAUDE.md says to treat every code block in a plan
as a draft.

1 files changed, 28 insertions, 0 deletions

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index d1d8a29..1af49bb 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -68,9 +68,37 @@ add_qtmaildir_test(searchterm)
 add_qtmaildir_test(busyindicator)
 add_qtmaildir_test(tagstrip)
 add_qtmaildir_test(messagedetailsdialog)
+add_qtmaildir_test(markdownrenderer)
+add_qtmaildir_test(messagebuilder)
+add_qtmaildir_test(maildirname)
+add_qtmaildir_test(draftstore)
+add_qtmaildir_test(messagesender)
+add_qtmaildir_test(composecontext)
+add_qtmaildir_test(formattoolbar)
+add_qtmaildir_test(senddialog)
 add_qtmaildir_test(translations)
 # Asserts on the tracked .ts rather than the generated .qm: an untranslated
 # string is dropped by lrelease, so it is invisible in the .qm and shows up
 # only as English in a running Italian UI.
 target_compile_definitions(test_translations PRIVATE
     TRANSLATIONS_DIR="${CMAKE_SOURCE_DIR}/translations")
+
+# The notmuch hooks (assets/hooks/), which are Python rather than C++ and are
+# therefore registered directly rather than through add_qtmaildir_test().
+#
+# They run against the user's REAL mail on every sync, so they belong in the
+# suite rather than beside it as scripts someone remembers to run. Two of the
+# three need `notmuch` on PATH and build a throwaway database in a temp
+# directory; none of them touches the real one.
+#
+# No QT_QPA_PLATFORM here: nothing Qt is involved.
+find_package(Python3 COMPONENTS Interpreter)
+if(Python3_Interpreter_FOUND)
+    foreach(hook_test mailrules post_new qtmaildirconf)
+        add_test(NAME hooks_${hook_test}
+                 COMMAND ${Python3_EXECUTABLE}
+                         ${CMAKE_SOURCE_DIR}/assets/hooks/test_${hook_test}.py)
+    endforeach()
+else()
+    message(STATUS "Python3 not found: the notmuch hook tests will not run")
+endif()