state-specific icons

- add html snapshots for all the states of an issue and PR (draft/open/different kinds of closed, etc)
- parse them into the spot
- render them in the table
- **hard part** - items will change state after they were sent/closed. how do we handle that?
- if we adopt #98
- we could set icon on a per-URL basis, so when the icon transitions for a given issue or PR url, we change all the icons for that URL

No files, tests, or entry points are named. Start by tracing how issue and pull-request states are parsed and rendered in the table, then examine how the proposed #98 per-URL approach could handle later state changes. Done means HTML snapshots cover the listed states, those states produce the expected icons, and transitions update all icons for the same URL.

索引モデルが issue の本文から書いたものです。