use copy text to clipboard button

[milahu]

when i select text, i get a toolbar popup with a copy button:

<div class="copy-content_wrapper" aria-relevant="all" aria-live="polite"><button class="selection-button copy icon " aria-label="Copy"><ion-icon src="data:image/svg+xml;..." class="selection-popover-icon ios" role="img"></ion-icon></button></div>

pro: avoid openAI API calls

con: the text has no formatting. headings and paragraphs are joined into one line

this "expected text" could be used to correct the output of tesseract OCR
which has the correct formatting but can have broken text