tansy converts: three entries, no shelf

Publishes what the tool guarantees, on a condition that fired rather than a
decision reversed. Records the narrower promise that replaced promising the command
surface — a change to it lands on the page consumers already lock, so a rename
reports 200 the day it happens.

And records a limit found by accident that follows from a guarantee rather than
from anybody's code: an ETag is opaque, we promise never to interpret one, so two
of them can be compared and never ordered. A consumer can know two versions
disagree and can never know which is behind. Anybody building freshness on this
inherits it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018UTxuSizozEA8yDitPuris

.loom/externals/git.hypertheory-labs.dev/loom/externals/externals.md

@@ -62,6 +62,7 @@ what to decide are not.**
 
 - **where it was fetched from** — *resolved, as above*
 - **the publisher's `ETag`** — *verbatim*
+- **the visibility the source could be read at, when it was fetched**
 
 **It is committed**, because the thing it locks is committed, and *a lock that
 travels separately from what it locks is the drift this is meant to prevent.*
@@ -71,6 +72,26 @@ travels separately from what it locks is the drift this is meant to prevent.*
 > asserts your copy is the one being served, which is the thing you were going to
 > check.
 
+### Why visibility is in the lock and not left to the moment
+
+**Access is checked once and the copy is durable.** *A token gets you the read;
+nothing revisits it afterwards.* **So the adoption's legitimacy rests on the
+relative visibility of two repositories — and that is changeable by a checkbox, a
+year later, by somebody who never saw the adoption.**
+
+> **Record `public` or `not-public`. Never `private`.** *An anonymous request can
+> tell you a repository is not public. It cannot tell two repositories private to
+> **different people** apart* — **which is exactly the case where private into
+> private genuinely widens access.** *Record the word you can verify.*
+
+**Checking it costs one request per run, not one per document**, *because the only
+thing that must be current is **your own** visibility.* **Re-check a source only
+when the alarm would fire** — *you are public, it was recorded not-public* — *and
+if it has since gone public, update the lock and say nothing.*
+
+*A stored visibility decays in both directions, which is why the alarm re-checks
+rather than trusting the record.*
+
 ## Freshness is a conditional request
 
 **Locked on the publisher's `ETag`, verbatim — never a hash you compute.** *A