Draft capability entry (reuse-surface REUSE-WP-0017-T04, cohort 2)

Honest first-pass maturity vector grounded in README/docs/tests present
in this repo; no invented evidence. Flagged for human review before
publish. See reuse-surface history/2026-07-06-coverage-classification.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

registry/indexes/capabilities.yaml

@@ -1,4 +1,19 @@
 version: 1
-updated: '2026-06-16'
+updated: '2026-07-06'
 domain: helix_forge
-capabilities: []
+capabilities:
+- id: capability.communication.markitect-source-adapters
+  name: Markitect Source-Format Adapters
+  summary: Concrete source-format adapters (EPUB3, PDF) converting external document formats into canonical
+    Markitect Markdown, implementing the markitect-tool source adapter contract.
+  vector: D2 / A1 / C1 / R0
+  domain: communication
+  status: draft
+  owner: markitect-filter
+  path: registry/capabilities/capability.communication.markitect-source-adapters.md
+  tags:
+  - markitect
+  - adapter
+  - document-conversion
+  consumption_modes:
+  - library import (plugin/entry-point)