Eng-council: alignment checks from sweep findings + metrics baseline

.claude/skills/alignment/SKILL.md

@@ -40,6 +40,10 @@ Review all changes in scope. If changes span multiple patterns below, apply all
    over-engineering from iterative development — dead code, try/catch around internal calls
    that can't throw, abstraction layers wrapping a single implementation. Proceed with caution;
    ask if unsure.
+   - **Export hygiene**: a symbol is exported only if another module imports it. Symbols used
+     only within their module (including `as const` arrays that exist to derive a type) stay
+     unexported — `export type` the type, not its source array. Verify with Grep before
+     exporting "for future use"; the future caller can add the export.
 
 5. **Styles and UI**: When altering CSS or layout, follow or generalize existing patterns
    (CSS Modules + design tokens in `styles/tokens.css`) rather than writing from scratch. Don't
@@ -128,6 +132,9 @@ Update relevant docs if the feature is significant:
 If `package.json` changed:
 
 - Flag each new dependency; explain what it does and why it's needed.
+- Every package imported directly in `src/` must be declared in `dependencies` — never rely
+  on a transitive install (it can vanish or drift on any lockfile churn). Declaring a package
+  the bundle already carries adds no weight.
 - Could a small custom implementation avoid it? Note the trade-off.
 - Prefer dependencies that solve genuinely hard problems (parsing, rendering) over those that
   save boilerplate.

docs/codebase-metrics.md

@@ -0,0 +1,15 @@
+# Codebase Metrics
+
+One row per `/eng-council` sweep. The trend is the point: accretion becomes visible
+instead of felt. Methodology: LOC excludes `*.test.*`; "dead exports" is `npx knip`
+unused **runtime** exports (unused exported _types_ tracked in the sweep report, not
+here); "dup %" is `npx jscpd src --min-tokens 50 --format "typescript,tsx"` (tests
+included — they dominate the clones; non-test clones are itemized in the sweep report).
+
+| date       | src files | src LOC | core LOC | app LOC | deps | knip dead exports | jscpd dup % |
+| ---------- | --------- | ------- | -------- | ------- | ---- | ----------------- | ----------- |
+| 2026-06-12 | 105       | 16876   | 4669     | 12130   | 12   | 0                 | 2.69        |
+| 2026-06-12 | 106       | 16695   | 4655     | 11963   | 12   | 0                 | 2.03        |
+
+The second 2026-06-12 row is the same sweep after its structural proposals landed
+(usePopover/useColResizeDrag extraction, modal-cycle break, dead service deletion).