chore(template): clean-slate template snapshot from bb4a0c7

Curated, product-agnostic snapshot of the post-story-04 tree: demo
content deleted, auth-only reference feature, web-next shell, all gates
green. Product-specific docs, ADRs 027-029, PRDs/epics/archive, editor
library traces, and product naming are curated out; generic template
repairs (coverage provider devDeps, root test:coverage script, live
lint fixes, root-only release-please) are kept. See TEMPLATE.md for
provenance, curation list, and usage.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016j8z4VHjedXDTjEDNg7qHK

packages/core-eslint/rules/no-relative-parent-import-in-tests.js

@@ -0,0 +1,49 @@
+/**
+ * Feature test files import from `src/` through the `@/` alias, never via
+ * `../` parent traversal (CLAUDE.md "Key Conventions"). A `../` import in a
+ * test file is always reaching across `src/` directories — `@/` keeps those
+ * imports stable under file moves and makes the test's dependencies legible.
+ *
+ * Scoped to feature packages (`packages/<name>/src/`, excluding `core-*`):
+ * the convention is part of the feature template's contract. Core packages
+ * are generated and governed by their own templates, and tooling packages
+ * (turbo/generators, scripts) legitimately use relative paths.
+ */
+function isFeatureSrcTestFile(filename) {
+  const normalized = filename.replace(/\\/g, "/");
+  if (!normalized.endsWith(".test.ts") && !normalized.endsWith(".test.tsx")) {
+    return false;
+  }
+  return /\/packages\/(?!core-)[^/]+\/src\//.test(normalized);
+}
+
+/** @type {import("eslint").Rule.RuleModule} */
+export default {
+  meta: {
+    type: "problem",
+    docs: {
+      description:
+        "Feature test files must import src modules via the @/ alias, not ../ parent paths.",
+    },
+    schema: [],
+    messages: {
+      relativeParentImport:
+        'Test file imports "{{source}}" with a ../ parent path. Use the "@/" alias for src imports (e.g. "@/application/...").',
+    },
+  },
+  create(context) {
+    if (!isFeatureSrcTestFile(context.filename)) return {};
+    return {
+      ImportDeclaration(node) {
+        const source = node.source.value;
+        if (typeof source === "string" && source.startsWith("../")) {
+          context.report({
+            node: node.source,
+            messageId: "relativeParentImport",
+            data: { source },
+          });
+        }
+      },
+    };
+  },
+};