Signed-off-by: Moritz Poldrack <git@moritz.sh>

When started without specifying a fileupload backend, soju crashes
because of a nil-pointer deref.

	panic: runtime error: invalid memory address or nil pointer dereference
	[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x9484bd]

	goroutine 1 [running]:
	main.loadConfig()
		git.sr.ht/~emersion/soju/cmd/soju/main.go:94 +0x51d
	main.main()
		git.sr.ht/~emersion/soju/cmd/soju/main.go:127 +0x165
	panic: runtime error: invalid memory address or nil pointer dereference

Add a guardclause preventing that crash.

Signed-off-by: Moritz Poldrack <git@moritz.sh>

Co-authored-by: delthas <delthas@dille.cc>

Co-authored-by: delthas <delthas@dille.cc>

This extension is now widely deployed, so we will stick to
backwards-compatible changes only.

Same as wss:// and ws+insecure://, except we'll be able to add more
endpoints for future features (e.g. file uploads).

go-sqlite3 does not build with musl 1.2.4+, which is packaged in some
distros (e.g. Alpine 3.19+). This update fixes it. More info:
https://github.com/mattn/go-sqlite3/pull/1177

References: https://todo.sr.ht/~emersion/soju/156

Using an expired context will never actually send the error message
here.

The library prepends "mailto:".

That way the script fails if the reload fails.

Same as the soju extension.

The fix has been merged upstream.

using the sqliteQueryTimeout means a `undefined: sqliteQueryTimeout`
when building with `-tags=nosqlite`

The error message is clear enough already.

No need for the "!!" hack, an empty password field means that
auth is disabled already.