hive-sh4re + docs: extract LooseEnd wire-shape prose (#717 batch 4)

docs/conventions.md

@@ -91,6 +91,58 @@ each id in a per-recipient in-memory set so the next `Recv` can tag
 the row with `redelivered: true`. Idempotent + cheap when there's
 nothing in flight, so the at-boot fire is unconditional.
 
+### Loose-ends wire shape
+
+`LooseEnd` is the per-row response shape for `GetLooseEnds` (both
+the agent-flavour and manager-flavour requests). Tagged enum so
+new thread kinds (forge PRs, long-running approvals from a
+privileged bot, etc.) can land later without breaking existing
+handlers. Each row carries enough context that the caller renders
+it directly as a bulleted list, no follow-up fetch needed.
+
+Per-flavour scoping is uniform across the three variants:
+
+- **agent-flavour** `GetLooseEnds` only surfaces rows the calling
+  agent has standing in. `Approval` rows only appear when the
+  calling agent is the manager (sub-agents don't submit
+  approvals). `Question` rows surface where the agent is `asker`
+  OR `target` (the routing semantics from the Ask/Answer
+  subsection above). `Reminder` rows are scoped to `owner ==
+  self`.
+- **manager-flavour** `GetLooseEnds` lists every pending row in
+  the swarm — full audit view.
+
+Per-variant fields:
+
+- `Approval { id, agent, commit_ref, description?, age_seconds }`
+  — `agent` is the affected agent (target of the spawn / config
+  commit), not the asker. `description` is the manager's free-text
+  blurb shown on the dashboard card. `commit_ref` is the
+  kind-specific payload (see `docs/approvals.md::Approval kinds
+  (wire shapes)`).
+- `Question { id, asker, target?, question, age_seconds }` —
+  `target = None` = operator-routed (dashboard); `Some(agent)` =
+  peer-to-peer thread.
+- `Reminder { id, owner, message, due_at, age_seconds }` —
+  `due_at` is the absolute unix timestamp the scheduler is
+  targeting; clients compute time-until-fire as `due_at - now`.
+
+`age_seconds` saturates at zero on any clock anomaly (back-step,
+unsynchronised wall clock, etc.) so the bulleted list never
+shows nonsense ages.
+
+`CancelLooseEnd { kind, id }` is the matching write surface. The
+`kind` enum (`Question` / `Reminder` / `Approval`) selects which
+underlying store the dispatcher reaches into. `Question` and
+`Reminder` cancel from either surface subject to ownership
+checks (asker for the question, scheduler for the reminder).
+`Approval` is manager-only — sub-agents don't submit approvals
+so they have nothing of their own to withdraw; their wire
+surface returns a clear error if they try. Cancelling an approval
+transitions the row to `ApprovalStatus::Cancelled` and fires
+`ApprovalResolved { status: "cancelled" }` so the dashboard pulls
+the card out of the pending pane.
+
 ## Async forms
 
 Dashboard + per-agent mutating forms carry `data-async`; a delegated