chore: cut 0.8.0

[GraemeF]

main has carried four squashes since v0.7.0, and nobody running bdi can reach any of them until a version is cut. One of the four is breaking, which this repository has called a minor bump at every version below 1.0, v0.4.0 and v0.7.0 included.

The notes say what a reader has to act on and leave out what they cannot. The badge chain is the only item that changes what an existing config draws, so it has the Upgrading section to itself. The row that has gone is quoted rather than described, because a reader who has that string on their screen searches a frozen page for the string. The collapsed line's wording and the gap between that row's cells are not mentioned at all: the line did not exist at v0.7.0, so nobody arriving from there ever saw what was corrected. There is no Maintenance section, because the range holds no dependency, CI, test or docs commit.

The README gains a row for F, which shipped in #76 without one. Until now the table's only case pair was / n N, one row for one meaning, so a reader who had met f as focus the selected bead's pane would read F as a variant of it. The two rows name the noun that separates them, a pane and the forest, and the whole forest is the program's own key hint for that row.

docs/bdi-frame.svg was read against the new id rule rather than assumed current, and it is unchanged by it. atlas-1 is the front of atlas-10 as a string, but the rule measures a bead only against the row above it and those two are drawn at the same depth. What would restyle that picture is a child whose id is its parent's with a dot and more on the end.