jobq-wire: move the generic graph projection into its own crate

The wire types were in hive-host-sock, which is the host *socket* crate — so
anything living there is core-shaped by construction, and the projection had
quietly grown two core dependencies to match: it selected roots by matching
NodeKind::Dag, and rendered payloads through free functions in hive-c0re that
nothing obliged a second host to write.

hive-jobq is the wrong home too. That crate is the scheduler — logic — and
folding presentation in means every consumer of it carries a JSON vocabulary
it may never serve.

So: a new hive-jobq-wire. A host implements WireNode for its payload N and
WireResource for its resource name R; GraphWire::wire_snapshot is
blanket-implemented for Graph<N, R> when both hold, and for nothing else. A
payload that has never said how it displays has no way onto the wire.

wire_snapshot takes the roots to serve rather than reading Graph::roots
itself. Nothing is ever removed from a Graph, so retention is a policy only
the host can hold; hive-c0re passes visible_roots(), which is the existing
MAX_HISTORY_DAGS bound selected structurally (a root is a node with no
parent) instead of by node kind.

Cargo.toml

@@ -12,6 +12,7 @@ members = [
   "hive-forge-notify",
   "hive-host-sock",
   "hive-jobq",
+  "hive-jobq-wire",
   "hive-matrix-mcp",
   "hive-metric",
   "hive-priv",
@@ -56,6 +57,7 @@ indicatif = "0.18"
 hive-sh4re = { path = "hive-sh4re" }
 hive-agent-sock = { path = "hive-agent-sock" }
 hive-jobq = { path = "hive-jobq" }
+hive-jobq-wire = { path = "hive-jobq-wire" }
 hive-core-agent-sock = { path = "hive-core-agent-sock" }
 hive-claude = "0.1"
 hive-host-sock = { path = "hive-host-sock" }