chore(spec): re-anchor authorable-surface.base.json past the 17.x tombstone age-out (#27015)

The committed anchor sat at 85c6d76, before dbf7e04 (#26599) aged
the <=16.x retirement kits out. A build that cannot reach origin/main
anchors on this file, and then has to date the 38 deleted tombstone lines
through the @objectstack/spec@17.0.0 release tag. An offline, tagless
clone cannot read that tag, so `@objectstack/spec#build` failed there
(the cloud EE image check). Re-anchored with
`pnpm --filter @objectstack/spec gen:authorable-surface-base` at
7eb613c, which carries those deletions in its own surface.

Co-authored-by: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QUs3Bshfmr8srPY21BVS4u

Author: claude