Extract binder package from citation-evidence (EBIND-WP-0001)

Extracts citation-evidence/src/binder/ into this repo as the standalone
@citation-evidence/evidence-binder package: headless binding service +
in-memory link repo, active-state machine, the SharedContracts §7
rect-registry contract (registry, change pumps, hooks, SVG overlay), and
the target-neutral reference FormRenderer.

- toolchain mirrors sibling extracted repos (pnpm/tsc/vitest/eslint);
  imports rewritten from @shared/@engine aliases to the engine's
  @citation-evidence/engine package specifiers
- dependency boundary (engine + anchor only; no source/work/umbrella)
  enforced via eslint no-restricted-imports
- docs: extraction inventory + contract deltas, ADR-0001 (reference UI
  kept as supported exports), refreshed README/SCOPE/INTENT, populated
  capabilities index
- typecheck + lint green, 37 tests passing

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/index.ts

@@ -0,0 +1,12 @@
+export * from "./repos";
+export * from "./services";
+export * from "./state";
+export * from "./visual-guide";
+export { FormRenderer } from "./FormRenderer";
+export type {
+  FormFieldSchema,
+  FormRendererProps,
+  FormSchema,
+} from "./FormRenderer";
+export { BinderProvider, useBinder } from "./BinderProvider";
+export type { BinderServices, BinderProviderProps } from "./BinderProvider";