"History" page - Use faster server side "difference" rendering, show ignored/triggered rows

[dgtlmoon]

todo

• Use the same rendering in the dashboard/UI as we use in the notifications (remove JS renderer, use same code, this means less code, faster renders for text)
• "Preview" page correctly shows highlighted ignore, trigger lines
• "Preview" page correctly shows highlighted ignore, trigger lines - automated test
• check "activate preview" for live filter editing shows ignored/triggers
• clean up words/lines/ignore whitespace diffing
• add improved API endpoint
• Compare from 1761411574 to 1761687856 based on same logic how the select dropdown calculates local dates?
• finish 'share as image'
• link to 'preview single version'
• fix highlight actions on 'preview' page
• highlight text should trigger dialog 'ignore, share as image' etc, tooltip?
• history could open from left slide out? UI option?
• finish options
• search text?
• check highlighting JS

RSS per watch too?

maybe some of this can be replaced with icdiff

related #3452

#3519 (reply in thread)