Move documentation conventions to DEVELOPMENT.md

[morisil]

Moves the ## Documentation conventions section — the semantic line breaks rationale and the ### Markdown soft wrapping in the IDE setup — from README.md to DEVELOPMENT.md.

Both parts address someone about to edit files in this repository, not someone evaluating the project or consuming the published artifact, so they sit better next to the other maintenance notes.

• README.md — section removed; the ## Development pointer now covers the conventions as well.
• DEVELOPMENT.md — section appended verbatim, heading levels unchanged; the intro is reframed, as "maintenance notes … update the build tooling and dependencies" no longer described the whole file.
• CLAUDE.md — the soft-wrapping anchor retargeted from README.md to DEVELOPMENT.md.

No prose was rewritten in the moved section.

🤖 Generated with Claude Code

[claude]

Review

Clean, well-scoped documentation move — content is preserved verbatim, and the CLAUDE.md anchor is correctly retargeted to DEVELOPMENT.md#markdown-soft-wrapping-in-the-ide. I checked the repo for any other references to the old README.md#markdown-soft-wrapping-in-the-ide / README.md#documentation-conventions anchors and found none outside this diff, so no dangling links remain.

Since this is a pure Markdown reorg (no code, no tests, no security-sensitive surface), the usual code-review categories mostly don't apply here. A couple of minor, non-blocking observations:

• DEVELOPMENT.md still ends without a trailing newline (pre-existing from before this PR, just now inherited by the appended section) — not introduced by this change, so not worth fixing here unless you're touching the file anyway.
• The reframed intro line in DEVELOPMENT.md ("Notes for working on this project itself: the conventions its documentation follows, and the tooling and dependency updates worth doing from time to time.") reads well and correctly reflects that the file now covers more than just tooling/dependency maintenance.

No functional or structural issues found. LGTM.