We are currently moving away from CocoaPods, as detailed in
monal-im/Monal#1685.

As part of this, we want to migrate from clemensg/sqlite3pod (current CocoaPod
dependency), to sbooth/CSQLite (new SwiftPM dependency), since the former does
not provide a Swift Package.

The two use different default SQLite compile flags. However, the SwiftPM
dependency offers SwiftPM traits that allow us to create an equivalent (besides
minor differences that don't affect us) configuration.

Support for SwiftPM traits are newly added in XCode. To use them, we must
update our Project Format version to XCode 26.3. However, CocoaPods breaks on
project formats above 16.0 due to changes to the way that shellScripts are
represented. In earlier versions, they are a single string, but in later
versions, they become an array, which CocoaPods doesn't expect (see
CocoaPods/CocoaPods#12794 for more info).

As a result - CSQLite with traits and CocoaPods can't co-exist in Monal. This
is a problem, because I planned to migrate everything (including SQLite) except
for some old-UI-only dependencies, which I planned to leave unmigrated on
CocoaPods until the old UI was deco'd. Some of these dependencies have no Swift
package and also receive no updates, and I want to avoid too much manual
packaging work for dependencies that will be removed anyway. The above
constraints mean that CSQLite must migrate as CocoaPods is deintegrated - i.e.,
it must be the final dependency to move over, if we wish to use traits to
maintain comparable compile options.

To avoid this issue, create a package that wraps and reexports CSQLite, but
defines the traits we need in Monal as the default. That way, the package can
be used in Monal without needing to set any custom traits, and our Project
Format can remain on XCode 15.0 for the time being.

Then, once the old UI is deco'd and CocoaPods is removed, we can silently
switch to upstream's CSQLite, which should not differ from us apart from our
default trait selection.