feat(webapp,run-engine,core,clickhouse): surface combined concurrency in metrics and dashboard - #4830

…tore views on rollback

The CK enqueue gauges (fast path and queued path) now sample total running
and the stored cap, so metric buckets fed only by enqueues no longer record
zero totals. The migration's down section recreates the pre-existing
materialized view definitions so ingestion keeps flowing after a rollback.
The per-key table reads only the page's overrides with one HMGET instead of
loading the queue's whole override hash.

The test harness splits a migration's up section on semicolons, so a
semicolon inside a comment yields a comment-only statement that ClickHouse
rejects as an empty query and every container-backed suite fails at setup.

Queue retrieve only asks the engine for total running when a total limit is
set, matching the list presenter and avoiding a pointless read for the
common uncapped case.

The total concurrency numbers come from live Redis, not the metrics
pipeline, so the column belongs in both tables rather than only behind the
queue metrics UI gate.

A separate Total column implied every queue should have one, and its dash
read as a missing limit on queues that never use concurrency keys. Only
queues that declare a totalConcurrencyLimit now change: their Limit cell
reads as per-key plus total (e.g. 1 /key, 3 total) and Running turns
warning-colored when the total cap is saturated. Plain queues are
unchanged.

The total cap gates keyed admissions, so the Running cell now warns off the
group count rather than the aggregate that also includes unkeyed runs.

…dashboard and metrics

Queue API responses expose concurrency.combined, the dashboard says
combined, and the new metrics columns are named combined_running and
combined_limit.

Queues that set a combinedConcurrencyLimit show it bracketed next to the
per-key limit with a fine dashed underline and an explanatory tooltip; the
Limit header tooltip is width-capped. Queues without one are unchanged.

The tooltip trigger is a button, so nesting it in the Limit cell's link made
clicking it navigate; it now renders as the cell's trailing adornment.

Also reflows an import to the formatter's current output.

The dequeue gauge ran before the loop, so a queue's first batch from idle
and its final drain were never sampled with their runs in flight and the
combined chart under-reported. The successful path now re-samples after
admissions; early returns keep the entry sample. Also documents that
combined.current is the declared cap, clamped at admit time.

…mit column

Removes the override-aware admit and gauge reads from the CK Lua scripts and
the per-key limit column, following the removal of runtime per-key overrides
from this stack.

…rrides

The class the ignore covered is deleted at this level, so the merged result
carries no dead-code exemption.

The plain dequeue gauge re-samples after admissions like the keyed one, the
repair path clears a keyed run's variant and group slots by concurrency key,
pause responses include the combined limit, stale wording and a leftover
changeset from before the rename are cleaned up, and two empty flag blocks
are removed from the fast-path scripts.