imsd, imsd-ofonod: let polkit decide call control, not the account name

The system-bus policies granted net.catcrafts.IMS1 and org.ofono to root
and to the account `user`, postmarketOS's default name, so on a unit
whose account is called something else dbus denied every Dial from the
dialer — nothing in imsd's journal, nothing on screen. A field user
found it by trial (alyx report 14, 2026-09-20; ims ledger F14).

Let any local account reach both names and have the daemons decide:
placing, answering or ending a call needs polkit's
net.catcrafts.IMS1.Voice (the active local session; not an ssh login, an
inactive session or a system service account). imsd-ofonod asks about
its own callers, since its calls reach imsd as root. Reads such as the
status and the call list are not gated, and a refusal is logged with the
sender; a `--session` run, the development mode without root or polkit,
leaves the gate off. The check is ImsdBus, a small GLib module both
daemons link; the package depends on polkit.

An upgrade restarts both daemons (the previous commit), so the open
policy faces the old, ungated daemons only until the apk transaction
ends.

Tested on the dev phone (KPN) in builds of this series; not every path
has run there.

packaging/APKBUILD

@@ -9,8 +9,9 @@ url="https://forgejo.catcrafts.net/Catcrafts/imsd"
 arch="aarch64 x86_64"
 license="GPL-3.0-only"
 # the media leg dlopen's the AMR-WB codecs; pw-record/pw-play drive PipeWire —
-# none of which abuild's .so auto-scan can see
-depends="modemmanager opencore-amr vo-amrwbenc pipewire-tools"
+# none of which abuild's .so auto-scan can see; polkit answers the daemons'
+# call-control check (ImsdBus)
+depends="modemmanager opencore-amr vo-amrwbenc pipewire-tools polkit"
 # clang/libc++ C++26 modules build (see Makefile); llvm-runtimes ships the
 # libc++ std module sources (/usr/share/libc++/v1/std.cppm) it precompiles
 makedepends="clang lld libc++-dev llvm-libunwind-dev llvm-runtimes glib-dev pkgconf"