Implement CE-WP-0009: wire umbrella to @citation-evidence/engine

Add link: dependency on citation-engine, retarget @shared/@engine aliases,
remove in-repo shared/engine copies. ADR-0002 accepted (option B).
172 tests, typecheck, and lint pass.

README.md

@@ -4,9 +4,9 @@ A document-centered evidence workspace for capturing, managing, presenting,
 and re-opening citations. The umbrella over the six-package design described
 in `INTENT.md` and `wiki/ArchitectureOverview.md`.
 
-During the MVP all code lives here under `src/` (see "Repository layout"
-below). Sister repos hold INTENT only — code migrates outward when each
-subsystem stabilises.
+Shared types and engine services live in the extracted
+[`@citation-evidence/engine`](../citation-engine/) package (`link:../citation-engine`).
+Remaining partitions stay under `src/` until each subsystem extracts.
 
 ## Documentation
 
@@ -24,10 +24,10 @@ Both are referenced from every workplan and from each sister repo's INTENT.md.
 
 ## Repository layout
 
+Requires sibling checkout: `../citation-engine` (see `package.json` `link:` dep).
+
 ```
 src/
-  shared/   # vocabulary, types, pure helpers      → becomes part of citation-engine
-  engine/   # services, repositories, event bus    → becomes part of citation-engine
   anchor/   # selector creation/resolution, viewer adapter contract → becomes evidence-anchor
   source/   # ingest, fingerprint, extraction, recovery → becomes evidence-source
   binder/   # evidence-to-target binding, visual guide → becomes evidence-binder
@@ -41,9 +41,9 @@ repo is intended to be a `git mv` plus a `package.json` cut — nothing more.
 
 ## Sister repos
 
-Peers under `~/`; each holds INTENT.md only during MVP:
+Peers under `~/`:
 
-- [`~/citation-engine`](../citation-engine/) — shared model + engine services
+- [`~/citation-engine`](../citation-engine/) — **extracted** shared model + engine (`@citation-evidence/engine`)
 - [`~/evidence-anchor`](../evidence-anchor/) — selectors + adapter contract
 - [`~/evidence-source`](../evidence-source/) — ingest, representation, recovery
 - [`~/evidence-binder`](../evidence-binder/) — binding, visual guide, rect registry
@@ -54,6 +54,7 @@ Peers under `~/`; each holds INTENT.md only during MVP:
 Requirements: Node 20 LTS (see `.nvmrc`) and `pnpm` 9.
 
 ```bash
+# citation-engine must be checked out next to this repo (../citation-engine)
 pnpm install
 pnpm dev        # vite dev server (once src/app/ has a real entry)
 pnpm test       # vitest one-shot