Make compilation ID required - #131

The empty-context history was attributed to the wrong PR: #145 dropped
`minProperties: 1` and the `required` entry, but the context schema's
`anyOf` still rejected an explicit `{}` until #150 replaced the union
with `if`/`then` clauses. #131 likewise never declared the compilation
`id` required in prose; it only dropped the "optional" wording.

Every `Schemas:` list now names each schema file the change touched,
verified against the diffs. The #284 entry is split, since the segment
offset carry and the `$this` circularity rule are separate changes with
separate consequences. The encoding label rule is marked as a normative
tightening no validator catches, and its canonical label is described as
preferred rather than required, matching the schema. The id uniqueness
requirement is presented as the new part of #172, and `frame`'s values
as examples rather than an enumeration. The preamble explains why this
file is keyed by the `@ethdebug/format` version, and the history ends at
`0.1.0-0`.