Stub orgs surface in registry; overview citations redesigned

Added

• Stub organizations appear in the registry catalog — orgs known from a releases.json manifest but not yet ingested are listed with a stub badge; GET /v1/orgs/:slug and the domain-lookup endpoint return their declared source locations; MCP get_organization and lookup_domain surface stub status and declared release locations instead of an empty sources list.

Changed

• Org overview citation style rebuilt — the Sources section now links to release pages on releases.sh rather than placing inline superscripts; cited sources link inward to the canonical release URL when available and carry CreativeWork JSON-LD for SEO; the fenced-JSON citation format is retired.

Fixed

• Raw JSON citation blocks no longer appear in org overviews — a generation-truncation edge case was leaking an unterminated JSON code block into the overview body; affected overviews have been repaired.
• Emoji sprites and CI-status badges no longer appear in newly indexed release media — the media pipeline now filters WordPress emoji sprites and CI badge URLs before mirroring.