[codex] Move edit result shaping into workspace

[kostyafarber]

Summary

• Adds workspace-domain edit result structs for glyph value and structure edits.
• Moves changed-entity ownership into shift-workspace, so workspace edit methods return the edited layer plus touched IDs.
• Simplifies bridge mutation methods so they parse NAPI inputs, call workspace, convert the workspace edit result to shift-wire, bump the live version, and return.

Why

PR A makes edits target LayerId directly. This stacked PR tightens the next boundary: bridge should not decide which point/contour IDs changed for a domain edit. That belongs beside the workspace mutation because it is part of the edit semantics and persistence path.

The dependency direction stays clean: shift-workspace does not depend on shift-wire or NAPI. Bridge remains the wire/NAPI adapter.

Validation

• cargo check -p shift-workspace -p shift-bridge
• cargo test -p shift-workspace -p shift-bridge
• pnpm --filter shift-bridge run test
• cargo clippy -p shift-workspace -p shift-bridge --all-targets -- -D warnings
• commit hooks: cargo check/fmt/clippy/test