Direct-C: 2D array shape returned incorrectly

Direct-C returns wrong shape for 2D allocatable arrays (shows (0,0) instead of actual size).

**Reproduction:** (requires #329 fixed first)
```bash
cd f90wrap/examples/default_i8
make -f Makefile.meson DIRECTC=yes clean test
```

**Error:** `IndexError: index 0 is out of bounds for axis 1 with size 0`

**Affected:** default_i8