fix: don't infer archive nesting from paths in error text

`ProcessPathErrors` cut the `path="..."` it pulled out of an error at the first `!/` and built nested
coordinates from it, so a host file with `!/` in its name was reported as a file inside an archive.

- paths from error text are taken as plain real paths again, as on main
- the php extension reader already has the location in hand, so it records the unknown against that
  instead of re-parsing the error (this is the one caller that could see a nested path). It also
  no longer defers `Close` on a nil reader when the read fails

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

internal/unknown/path_error_test.go

@@ -35,6 +35,13 @@ func Test_ProcessPathErrors(t *testing.T) {
 				Reason:      fmt.Errorf(`path="/var/lib/thing" suffix`),
 			},
 		},
+		{
+			errorText: `path="/data/Hello!/world.txt"`,
+			expected: &CoordinateError{
+				Coordinates: file.NewCoordinates("/data/Hello!/world.txt", ""),
+				Reason:      fmt.Errorf(`path="/data/Hello!/world.txt"`),
+			},
+		},
 		{
 			errorText: "all your base are belong to us",
 			expected:  nil,