chore(spec): advance the committed authorable-surface anchor to b9598e9

The maintainer's ruling on batch #135 item 3 (letter A) directs this PR to carry
a second, separate commit that advances the committed anchor with
`pnpm --filter @objectstack/spec gen:authorable-surface-base`.

`authorable-surface.base.json` was anchored on 53ef057 (7836 keys) and is
now anchored on b9598e9 (7772 keys), the merge base this branch resolves
against origin/main after the preceding merge commit.

Why it is owed: this branch widens the reachability root set from 26 to 30, so
two keys that main had already retired through the guidance route stopped being
waivable as "def not reachable from the metadata-type roots". Against the stale
anchor a shallow CI checkout reads them as deletions this branch made:

    2 authorable baseline line(s) were deleted without proof (#4650):
      - data/Metric:filters
      - integration/DataSyncConfig:schedule

Both retirements are already on main. Advancing the anchor is the deliberate
maintenance act the build's own output names; it forgives no future deletion,
and a bare deletion of a reachable key is still refused on the advanced anchor.

Claude-Session: https://claude.ai/code/session_01KB5PFtxuy1x3dcR5gxudx6
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude