Docs: add plain Wesley onboarding path #678

Problem

The README quick start is usable, but deeper docs still require too much internal vocabulary before a new GraphQL/Rust contributor can understand the product surface.

Evidence at e948217274fe:

• README.md:40 has a normal quick start.
• README.md:56 shows schema lower and emit commands.
• README.md:118 introduces external module examples.
• docs/GUIDE.md:148 foregrounds HOLMES / Watson / Moriarty / BLADE.
• docs/GUIDE.md:171 introduces Realization Shells and Witness Surfaces.
• docs/WESLEY_GLOSSARY.md:168 defines the assurance vocabulary.

The vocabulary is useful internally, but it is a tax on first-hour adoption.

Mitigation Plan

• Create a Plain Wesley docs track: GraphQL in, deterministic JSON IR out, optional Rust/TypeScript/codec emitters, external target owns meaning.
• Move toolchain/mythology terms behind an advanced assurance vocabulary page.
• Add a standard GraphQL-to-Wesley term map: SDL, type, field, directive, operation, schema hash, L1 IR, emitter.
• Add one beginner tutorial: install CLI, lower a schema, inspect IR, emit Rust, emit TypeScript, validate manifest.
• Add one contributor tutorial: add a simple generic emitter field behavior with test-first workflow.
• Add a docs/release rule: new public nouns need a plain-English alias or must be marked internal/experimental.

Acceptance Criteria

• A new user can complete the first tutorial without reading the glossary.
• The guide clearly separates compiler basics from advanced assurance/toolchain vocabulary.
• Docs-check/preflight cover any new routed docs pages.