Un-hard-wrap all Markdown documentation

Every prose paragraph and list item was manually wrapped at ~80-100
columns; joined each back into a single line. Headings, table rows,
and fenced code blocks are untouched -- tables already had one row per
line, and wrapping inside a code fence is the code's own formatting,
not something this applies to.

Also fixed two pre-existing typos this surfaced (both from wrapping
without leaving the space that was actually intended): a missing space
in "{ challenge_id, options }" and a stray "+ TypeScript" that had
accidentally been written as if it were a new line, in web/README.md
and README.md respectively.

Code comments are explicitly out of scope for this -- left exactly as
they were.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/history.md

@@ -1,10 +1,6 @@
 # Development history
 
-A stage-by-stage log of major features, in the order they landed. Each row
-describes the app as it was *at that point* — later stages sometimes
-superseded earlier ones (e.g. password login, added in stage 1, was removed
-again in stage 12); see [docs/api.md](api.md) and
-[web/README.md](../web/README.md) for how things work now.
+A stage-by-stage log of major features, in the order they landed. Each row describes the app as it was *at that point* — later stages sometimes superseded earlier ones (e.g. password login, added in stage 1, was removed again in stage 12); see [docs/api.md](api.md) and [web/README.md](../web/README.md) for how things work now.
 
 | Stage | Scope | State |
 |-------|-------|-------|