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>

registry/indexes/capabilities.yaml

@@ -1,4 +1,18 @@
 version: 1
-updated: '2026-06-16'
+updated: '2026-07-08'
 domain: helix_forge
-capabilities: []
+capabilities:
+  - type: library
+    title: Evidence-to-target binding
+    description: >-
+      Links evidence items to structured targets (form fields, claims,
+      requirements) with relation/status/confidence and two query directions,
+      emitting canonical engine bus events.
+    keywords: [evidence, binding, evidence-link, form-field, citation-evidence]
+  - type: library
+    title: Visual-guide rect registry
+    description: >-
+      The SharedContracts §7 rect-registry contract — independent renderers
+      publish field/evidence-card/highlight rects into one registry; an SVG
+      overlay draws the active-triple guide without polling.
+    keywords: [rect-registry, visual-guide, overlay, active-state, citation-evidence]