docs: switch author attribution from "Stephen Waits" to SWaits

Per maintainer's preference, the project's outward-facing copy now
refers to the author as [SWaits](https://swaits.com/) instead of
his legal name and email address.

Touched in this commit:
- src/00-overview.md (Status and Provenance callout)
- README.md (Provenance section + Author section; the email
  steve@waits.net is dropped — swaits.com is now the canonical
  contact)
- book.toml (authors = ["SWaits"], plain text since TOML)
- versions/v0.1.0/00-overview.md (regenerated via
  `just cut-version v0.1.0` after src/ was updated)

Git author identity on commit metadata is a separate, git/jj-config
concern and is intentionally not touched.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

book.toml

@@ -1,6 +1,6 @@
 [book]
 title = "MeshCore Protocol Specification"
-authors = ["Stephen Waits"]
+authors = ["SWaits"]
 description = "An independent, AI-authored specification and conformance test corpus for the MeshCore mesh networking protocol. The official MeshCore C++ firmware is the source of truth; this spec is downstream."
 language = "en"
 src = "src"