[M10] Define editor-neutral language-service and workspace model

[Teakowa]

Parent: #27

Depends on: #62

Planning status: provisional until the M9 gate is complete.

Goal

Define Wright-owned language-service contracts for documents, workspaces/projects, positions, symbols, diagnostics, and semantic queries before introducing LSP protocol types.

Scope

• Define document identity/version and project/workspace ownership over the existing compiler/session model.
• Define editor-neutral requests/results for language intelligence that reuse native frontend and semantic services.
• Define mapping between source positions/ranges and compiler source provenance.
• Define lifecycle for open/changed/closed documents without making the filesystem state ambiguous.
• Define capability boundaries between language-service core and protocol adapters.
• Reuse M9 source-edit/refactoring contracts where appropriate.

Non-goals

• Implementing LSP wire handling in core.
• Shipping editor extensions or UI.
• Duplicating compiler/project models solely for editors.

Acceptance criteria

• Core language-service operations can be expressed without importing LSP types.
• Document/workspace state has deterministic ownership and version semantics.
• Source/project resolution matches CLI/toolchain behavior rather than creating an editor-only interpretation.
• The model supports later diagnostics, navigation, completion, rename, and semantic-token work.

[Teakowa]

Delivered in commit 7b0d0f2 (crates/wright-language: document.rs, service.rs; docs/language-services.md).

• Editor-neutral Document/DocumentStore: URI identity, text, monotonic internal version, project root; open/change/close lifecycle with version bumping.
• Editor-neutral requests/results (positions, ranges, diagnostics, hover, definition, references, completion, rename, semantic tokens) reuse the native frontend, semantic index/analyzer, and workshop catalog — no LSP types anywhere in the core.
• Position/range conversion at the service boundary (0-based editor ↔ 1-based compiler spans); results carry document version so filesystem state is never ambiguous.

[Teakowa]

Remediated and re-verified (commits c4fc954..c8c17b2).

• Document.version is now the client's textDocument.version (i32), not an internal counter; DocumentStore::change rejects stale/out-of-order versions.
• Source-aware SourceLocation { source, range } preserves span.file provenance; span_to_range is UTF-16-aware and Document::to_line_col converts UTF-16 → compiler character columns.
• Workspace root is resolved from LSP initialize rootUri/workspaceFolders (not cwd).
• Open-document overlays participate in include resolution via preprocess_with_overlay/the store overlay map.
  Tests: document unit tests (version preservation, stale rejection, UTF-16 non-BMP), overlay tests, cross-file tests.