docs(engagement): Phase 13 as built, and Phase 14 -- retention

Phase 13 was the only phase in the workstream with no as-built section, which
6.0b makes a phase's own deliverable. It has one now, and it has something to
record beyond "it merged":

  * the window missed steps 5 and 7 (Integration-kit, runicgateway.com); they
    landed afterwards, with a third PR clearing a leftover from step 4;
  * Gitea's `raw` API route is CDN-cached for six hours, and a stale read fails
    BOTH ways -- it failed a correct site AND reported an already-republished
    bundle as current. All three cross-repo checks read `contents` now;
  * the Integration-kit equality check never goes red on its own. It clones the
    ref the kit itself pins, so the kit sat three minor versions behind, green,
    for the whole workstream. Step 5 is the only thing that makes anyone look;
  * `registerEngagementSeeds` does not validate the body it seeds, and the kit's
    own example was malformed. Only a run through core's REAL registry found it,
    which the kit's CI does not do and cannot;
  * every `edge` was deleted rather than fast-forwarded. Recorded as the
    convention, because a branch that does not exist cannot be branched from
    stale -- which was 6.0a's actual failure.

Phase 12's second finding becomes **Phase 14**, scoped and not started: four
tables with no retention sweep, and they are not one problem with one horizon.
`engagementCooldowns.db.prune()` already exists with no caller; the send log has
two live readers (the hourly cap's index and the operator screen) that bound how
short its horizon may be; and suppressions probably should NOT expire at all,
because ageing out a bounce re-mails an address that already hard-bounced. The
phase owes `/privacy` and the Play answers, which today say "nothing here expires
on its own" -- true now, false the moment it lands.

Also: ticks on the phase headings that were done and unmarked (4, 9, 10, 11, 12,
13), a status header that still said everything from Phase 10 on was design, and
three status lines that outlived the cutover -- `link/v5.md` and this README's
index row both said protocol 5 was built but unreleased, and INTEGRATION.md named
the v2.0.0/v1.0.0 pairing as the shipped one.

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

link/v5.md

@@ -1,6 +1,6 @@
 # Protocol 5 — Three enrichments, one bump
 
-**Status:** Built, on `edge`. Not yet cut over to `main`, so not yet released.
+**Status:** Released. Cut over to `main` on 2026-09-01 and shipped in sidecar **v2.1.0** + overlay **v1.1.0**, paired as bundle **2026.09.01**.
 **Date:** 2026-08-31
 **Codebase:** ServUO 57.4, `<servuo>`, net48 / x64, Expansion **EJ**.
 **Companion to** [`PLAN.md`](PLAN.md) (1.0 read/event plane), [`PROTOCOL_2.md`](PROTOCOL_2.md) (2.0 provisioning + world-state streams), [`v3.md`](v3.md) (3.0 shard content + the visibility framework), [`v4.md`](v4.md) (4.0 guild membership), [`INTEGRATION.md`](INTEGRATION.md) (website API).