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-0004-requirement-test-governance.md

@@ -0,0 +1,40 @@
+---
+id: SLICE-0004
+type: slice
+status: ready
+parent: NS-0001
+title: Keep requirement and test governance aligned
+refs:
+  - REQUIREMENTS.md
+  - AGENTS.md
+  - redgate
+---
+
+## Objective
+
+Keep behavior-changing test work tied to checkable requirements without turning redgate cleanup into unrelated product scope.
+
+## Authority
+
+`AGENTS.md` requires reading and updating `REQUIREMENTS.md` when behavior changes, citing relevant `req:` IDs, and running redgate commands when requirements change.
+
+## Close when
+
+- Behavior-changing test slices cite the requirements they constrain.
+- Requirement-only maintenance is separated from behavior implementation.
+- `redgate health --strict` and `redgate lint` are green for the changed scope.
+
+## Verification
+
+- `redgate health --strict`
+- `redgate lint`
+- Relevant behavior test from the implementation slice.
+
+## Non-goals
+
+- Do not add citation-only padding.
+- Do not make redgate adoption or formatting the product payoff.
+
+## Evidence
+
+The repo already uses `REQUIREMENTS.md`, redgate, and `req:` citations as durable governance authority.