docs/jobq.md: drop the core-specific node table, keep only the abstract engine explanation

mara: "only the abstract jobq part was asked for in the first place" —
the previous revision still carried the full hive-c0re step-kind table
under a "core-specific nodes" heading; that catalogue belongs in
coordinator.md (where it already lived) alongside the rest of
hive-c0re's job-queue internals, not duplicated here.

jobq.md is now just the domain-agnostic model (graph of steps + shared
resource slots) plus the generic row/step/glyph framing for watching it
in the dashboard — no hive-c0re-specific step names anywhere.
Coordinator.md's job-queue section, docs/README.md, and the root
CLAUDE.md reading-paths index are updated to match.

CLAUDE.md

@@ -242,11 +242,11 @@ read them à la carte.
   endpoint authenticate a pushing hive, and what does a snapshot
   actually contain?"** →
   [`docs/snapshot-store.md`](docs/snapshot-store.md).
-- **"What am I looking at in the build queue? What does each step
-  mean?"** → [`docs/jobq.md`](docs/jobq.md) (operator-facing, no
-  implementation detail).
-- **"How does the rebuild queue work internally? What are queue kinds and
-  sources?"** → [`docs/coordinator.md`](docs/coordinator.md).
+- **"What is the job queue, as a general idea?"** →
+  [`docs/jobq.md`](docs/jobq.md) (operator-facing, no hive-c0re specifics).
+- **"How does the rebuild queue work? What are the concrete step kinds,
+  queue sources, scheduler internals?"** →
+  [`docs/coordinator.md`](docs/coordinator.md).
 - **"How does the CI runner work? What's the auto-registration flow?"** →
   [`docs/ci.md`](docs/ci.md).
 - **"What is `/knowledge`? How does the hive-wide knowledge repo sync,