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-0003-keyed-regression-boundaries.md

@@ -0,0 +1,40 @@
+---
+id: SLICE-0003
+type: slice
+status: ready
+parent: NS-0001
+title: Protect keyed collection regressions with generated-resource assertions
+refs:
+  - REQUIREMENTS.md
+  - examples/html_examples/src/main.rs
+  - hemx-test/src/lib.rs
+---
+
+## Objective
+
+Make keyed list regressions easy to catch without raw selector or raw effect coupling: tests should assert generated resource behavior for remove, replace, and append paths.
+
+## Authority
+
+`REQUIREMENTS.md` `list/006`, `test/008`, `test/009`, `test/010`, and `test/017` constrain keyed collection behavior and test diagnostics.
+
+## Close when
+
+- Filtered keyed collections are tested for removing filtered-out keys, replacing retained keys, and appending newly visible keys.
+- Assertions use generated resource helpers or `hemx_test` inspection adapters, not raw runtime ids as app-facing API.
+- Failure messages name generated resources where practical.
+
+## Verification
+
+- `cargo test -p hemx-html-examples`
+- `cargo test -p hemx-test --test inspector`
+- `cargo run -p hemx-xtask -- html-examples-smoke`
+
+## Non-goals
+
+- Do not add app authoring APIs for selectors or raw runtime ids.
+- Do not test private runtime payload layout unless the slice changes wire semantics.
+
+## Evidence
+
+The active-search example and `hemx_test` helpers already provide anchors for this regression boundary.