Replace the old path-to-version patching with full workspace inheritance
resolution.  Each member's Cargo.toml now has all `workspace = true`
references inlined from `[workspace.package]` and
`[workspace.dependencies]`,
and the root Cargo.toml is stripped of those workspace sections to
become a
pure virtual manifest.  Post-package extraction also adds a bare
`[workspace]` to each standalone crate so it remains a valid workspace
root.

Migrate existing doc scripts to call the deploy-api-docs tool, and add
nightly variants that build with --cfg docsrs

Add `#![deny(missing_docs)]` across multiple crates and fill in
documentation for all public items, including struct fields, enum
variants, trait methods, and proc macros.  Also mark two shell scripts
as executable.