docs(work): map testing and editor northstars

Add repo-local northstars and ready slices for testing strategy, LSP/editor completion, and hemplate highlighting boundaries.

work/slices/SLICE-0009-lsp-protocol-contract.md

@@ -0,0 +1,39 @@
+---
+id: SLICE-0009
+type: slice
+status: ready
+parent: NS-0002
+title: Harden LSP protocol behavior
+refs:
+  - hemx-lsp/src/main.rs
+  - docs/editor-support.md
+  - REQUIREMENTS.md
+---
+
+## Objective
+
+Make `hemx-lsp` predictable as an LSP server: initialize capabilities, document sync, completion, hover, diagnostics, shutdown, and unknown request errors should have focused protocol tests.
+
+## Authority
+
+`hemx-lsp/src/main.rs` implements the protocol loop; `docs/editor-support.md` names the editor-facing command surface.
+
+## Close when
+
+- Tests cover `initialize`, `didOpen`, `didChange`, `didSave`, `didClose`, `completion`, `hover`, `shutdown`, and unknown requests.
+- The tests assert JSON-RPC framing and response IDs, not just helper functions.
+- The server keeps normal HTML/tree-sitter tooling assumptions and does not add editor-provider policy.
+
+## Verification
+
+- `cargo test -p hemx-lsp`
+- `cargo run -p hemx-lsp -- help`
+
+## Non-goals
+
+- Do not add async runtime or background watchers unless protocol tests prove sync IO is insufficient.
+- Do not publish editor extensions in this slice.
+
+## Evidence
+
+The current LSP loop is small and testable through in-memory readers/writers.