breadcrumbs re-compositioon

• [x] write a new design guides file "composition.md"

• [x] research how svelte suggests using composition and props

• [x] choose one svelte component

• [x] describe how it uses composition and props

• [x] suggest how it could take more advantage of using them

• [x] create a check list of all components that could take more advantage

• [x] add a brief comment to each summarizing the nature of the change

• [x] read composition.md

• [x] add a new section called "migration of Breadcrumbs"

• [x] add checkbox items of all the steps

• [x] read breadcrumbs.md and implement phase 1

• [x] write a breadcrumbs migration strategy

• [x] read breadcrumbs.md and implement phase 2

• [x] add description of work performed

• [x] update the TOC

• [x] read breadcrumbs.md and implement phase 3

• [x] add description of work performed

• [x] make painfully certain that layout is not broken

• [x] write a new design guide: migration.md describe how do craft a <migrate-foo>.md document, based on everything we did and learned during this chat

• [x] read breadcrumbs.md and implement phase 4

• [x] add description of work performed

• [x] make painfully certain that layout is not broken

• [x] fix bugs introduced in phase 4

• [x] completely wrong in history

• [x] clicking the forward or the backward buttons causes utterly incorrect breadcrumbs

• [x] breadcrumbs react badly change in selection of an ancestry

  • [x] empty after launch
  • [x] FUBAR after selection
  • [x] becomes correct on graph mode switch

• [x] ACK! what a tangled mess

• [x] reverting back to end of phase 2

• [x] STOP!