Amend designs 51, 26, 32, 25 and 55 for the registry milestone

The registry move, seat definitions, declares, bus state and the knowledge base
ship as one milestone (ADR 0612, 0613), ordered by the module graph's edges
(ADR 0614), with the foundation parts' first view (ADR 0615) and the overview
page (ADR 0616). The designs said four deliveries, a seat-definition source
nobody serves, a checker naming mesh-config, and left the bus module's first
view, caller and deletion paths open; they now say what the milestone builds.
Adds the glossary words it uses, playbook 02's cites link for an abandoned
effort, and the hq-design-writer agent definition.

Claude-Session: https://claude.ai/code/session_01JG73KJNrH5EgFXMKKYSrig

00-META/process/01-research.md

@@ -163,7 +163,8 @@ for the operator's Approve on a channel that proves who answered.
 ## Closing
 
 An effort never just stops. It closes through playbook [02](02-graduation.md) as `graduated` or
-`abandoned`, always with a `became` link to what it turned into. Nothing is deleted — what was rejected,
+`abandoned`: a graduated effort with a `became` link to what it turned into, an abandoned one with a `cites` link to
+what replaced it (playbook 02 step 5). Nothing is deleted — what was rejected,
 and why, is the more expensive half to rediscover.
 
 ## How it is checked

00-META/process/02-graduation.md

@@ -62,7 +62,10 @@ about an hour, and said to the operator if it runs past.
    milestones, issues, and each milestone built as one feature step (playbook [07](07-feature-branches.md)).
 5. **Close the effort.** `knowledge-base.propose` the effort again, whole, with `status: graduated` and a
    `became` link to the decision record (`"NNNN"`) and to the design document (its path). An effort that
-   stops without a decision is proposed with `status: abandoned` and a `became` link to what replaced it.
+   stops without a decision is proposed with `status: abandoned` and a `cites` link to what replaced it: the
+   knowledge base refuses `became` from a research effort to another research effort (its link-fits rule, design
+   55 § 2), so a replacing effort is cited, and `became` stays for the decision and the design an effort turned
+   into.
 
 ## Writing a decision record
 
@@ -140,7 +143,9 @@ A design changes only through a decision.
 
 1. Write the decision record (above). If it reverses an earlier one, it `supersedes` it.
 2. Edit the to-be design document, add the record to its `decisions:` as `"ADR NNNN"`, and set `updated:`
-   to today. Review it by architectural domain before it is merged (playbook [01](01-research.md#review-by-architectural-domain)), and
+   to today. A set of amendments across several designs (a milestone's findings, a graduation's) is written by the
+   agent `hq-design-writer` (`.claude/agents/`), started with a handover naming the designs, the records and the
+   branch. Review it by architectural domain before it is merged (playbook [01](01-research.md#review-by-architectural-domain)), and
    rewrite its *Reviewed by architectural domain* section.
 3. If the amendment came from an issue, give the issue the document path in the issue tracker:
    `amended-design` on its `issue-tracker.move` to `resolved`, or `issue-tracker.link` with kind