Encoding for app
Allow importing `rotate` without rename again
Add some options and a new `mirror` preserving whitespace
Make `transpose` not drop trailing whitespace

Might lose alignment for possibly adding more columns here
Three different routes for rotate, mirror, transpose

Factors out most custom logic per operation. Also drops the separated
result/output page and just displays it inline, preserving the input.
Updates templates to read options and data based on current operation.
Navigation header