feat(entity): Chunk #4 remaining items — consistency UI, context rail, palette search, expanded seed & DATA_MODEL

- Consistency tab in EntitiesView surfacing findInconsistencies() results
- ContextRail + MentionPopover wired into WritingView for entity context/hover
- CommandPalette indexes entities and chapters for cross-entity search
- link field type for entity references in character fields
- findDeadCharacterMentions consistency check + tests
- Expand seed with a location, note, and a natural Elias Vell mention so the
  dead-character-after-death case is actually exercised
- Author docs/DATA_MODEL.md documenting core schemas, types, storage contract
- Rename CharacterMention id attr -> entityId to match core backlinks/consistency

packages/core/src/consistency.test.ts

@@ -3,9 +3,11 @@ import {
   findOrphanedMentions,
   parseRelationships,
   findRelationshipAsymmetry,
+  findDeadCharacterMentions,
   findInconsistencies,
   SYMMETRIC_RELATIONSHIPS,
 } from "./consistency.js";
+import { collectMentionsInDoc } from "./backlinks.js";
 import type { Character, Entity, ProseMirrorDoc } from "./types.js";
 
 const doc = (entityId: string | null, name = "Mara"): ProseMirrorDoc => ({
@@ -152,12 +154,32 @@ describe("findRelationshipAsymmetry", () => {
 });
 
 describe("findInconsistencies", () => {
-  it("combines orphan-mention and relationship-asymmetry issues", () => {
-    const chapters = [{ id: "ch1", title: "Ch 1", doc: doc("ghost") }];
+  it("combines orphan-mention, relationship-asymmetry, and dead-character issues", () => {
+    // Chapter mentions "ghost" (orphan) and "ada" (dead character still alive in prose).
+    const chapters = [
+      {
+        id: "ch1",
+        title: "Ch 1",
+        doc: {
+          type: "doc",
+          content: [
+            {
+              type: "paragraph",
+              content: [
+                { type: "text", text: "Ada met " },
+                { type: "CharacterMention", attrs: { entityId: "ada", name: "Ada" } },
+                { type: "text", text: " and a " },
+                { type: "CharacterMention", attrs: { entityId: "ghost", name: "ghost" } },
+              ],
+            },
+          ],
+        } as ProseMirrorDoc,
+      },
+    ];
     const ada: Character = {
       id: "ada", projectId: "p", name: "Ada", role: "", bio: "", appearance: "", voice: "",
       relationships: [{ targetId: "maria", kind: "sibling", note: "" }],
-      arc: "", status: "active", tags: [],
+      arc: "", status: "dead", tags: [],
     };
     const maria: Character = {
       id: "maria", projectId: "p", name: "Maria", role: "", bio: "", appearance: "", voice: "",
@@ -167,5 +189,36 @@ describe("findInconsistencies", () => {
     const issues = findInconsistencies(chapters, entities);
     expect(issues.some((i) => i.kind === "orphan-mention")).toBe(true);
     expect(issues.some((i) => i.kind === "relationship-asymmetry")).toBe(true);
+    expect(issues.some((i) => i.kind === "dead-character-mentioned")).toBe(true);
+  });
+
+  it("does not flag a dead character who is not mentioned in any chapter", () => {
+    const chapters = [{ id: "ch1", title: "Ch 1", doc: doc("ghost") }];
+    const ada: Character = {
+      id: "ada", projectId: "p", name: "Ada", role: "", bio: "", appearance: "", voice: "",
+      arc: "", status: "dead", tags: [],
+      relationships: [],
+    };
+    const issues = findDeadCharacterMentions(chapters, [ada]);
+    expect(issues).toHaveLength(0);
+  });
+
+  it("collects every entity id referenced in a doc", () => {
+    const docWithTwo = {
+      type: "doc",
+      content: [
+        {
+          type: "paragraph",
+          content: [
+            { type: "text", text: "Ada and " },
+            { type: "CharacterMention", attrs: { entityId: "maria", name: "Maria" } },
+            { type: "text", text: " met " },
+            { type: "CharacterMention", attrs: { entityId: "brad", name: "Brad" } },
+          ],
+        },
+      ],
+    } as ProseMirrorDoc;
+    const ids = collectMentionsInDoc(docWithTwo);
+    expect([...ids].sort()).toEqual(["brad", "maria"]);
   });
 });