fix(lanes): count every pipeline run, not one per lane

Lane Pipeline Pass Rates read `lanes.stages`, which is a snapshot of the
pass in flight: re-entering a node overwrites its record, and moving
backwards deletes every record ahead of the new stage. The report treated
one lane row as one run, so shipping ten features through a lane still
counted as one, and no node could ever exceed 1/1. History survived only
via `lane_features`, which is written when a feature is activated — a
path most users never take. The panel was not wrong, it was structurally
incapable of counting.

Add `lane_stage_events`, an append-only log written by every declaration
and every accepted detection, and aggregate from that. A run is one pass
through the template: the log starts a new one when the lane moves
backwards or leaves the template's last node. Existing snapshots are
seeded as one run each on first boot, so upgrading does not read as
"never run". Templates a lane is configured with are still listed at
zero — a pipeline going unused has to be visible as such.

Count inferred reaches too, in their own column and their own colour.
Detection stays out of the pass rate ("inference is never evidence"), but
reporting a stage the hooks demonstrably saw as "never reached" is what
made the panel look broken to anyone who works without running the
pipeline commands.

Also reject a stage naming no node of the lane's pipeline (400 EBADSTAGE,
listing the ones that exist) instead of storing it with a warning nobody
reads. A real lane had accumulated five such keys, one of them `test` on
a ship-feature lane whose CI node is `gates` — which is why that row read
never-reached while the stage had in fact been declared. Aliases still
resolve, so shorthand is unaffected.

bin/agenthub.js

@@ -2766,22 +2766,6 @@ async function cmdStage(args) {
     result: flag("result"),
   });
   console.log(`lane #${lane.id} → ${lane.stage} (${lane.progress}%)`);
-
-  // A stage name matching no node (nor alias) still stores — setStage takes the
-  // string verbatim — but phaseIdx() then returns -1, so nothing renders as
-  // `current` and progress reads 0. Warn, never fail: a typo must not break a
-  // declaration the pipeline can still record, but it must not pass silently.
-  // Skipped for `--result fail`, which paints the node `failed` rather than
-  // `current` and would otherwise look identical to an unknown stage.
-  const nodes = lane.pipeline_nodes || [];
-  if (flag("result") !== "fail" && nodes.length && !nodes.some((n) => n.state === "current")) {
-    console.error(
-      c.yellow(
-        `! "${stage}" matches no node in pipeline "${lane.pipeline}" — recorded, but the ` +
-          `pipeline map won't show it. Nodes: ${nodes.map((n) => n.id).join(", ")}`
-      )
-    );
-  }
 }
 
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