fix(manager-core): F-P-007 concurrent queue dispatch per tick

tick_queue_arm called list_active_queue_consumers() and then iterated
serially, awaiting one queue.claim(app, queue) per consumer. With N
consumers and a 100ms tick the worst-case throughput was
N × (claim + executor) / tick — one slow handler blocked every other
queue's progress on the dispatcher's task.

Replace the for-loop with `futures::stream::iter(consumers)
.for_each_concurrent(QUEUE_DISPATCH_PARALLELISM, …)`. The execution
gate already caps real script-concurrency to its permits, so this just
removes the dispatcher-side serialization.

QUEUE_DISPATCH_PARALLELISM = 32 (matches the default gate). Workspace
gains `futures = 0.3` so `for_each_concurrent` is available.

AUDIT.md anchor: F-P-007.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -830,6 +830,21 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "futures"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b147ee9d1f6d097cef9ce628cd2ee62288d963e16fb287bd9286455b241382d"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-executor",
+ "futures-io",
+ "futures-sink",
+ "futures-task",
+ "futures-util",
+]
+
 [[package]]
 name = "futures-channel"
 version = "0.3.32"
@@ -874,6 +889,17 @@ version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cecba35d7ad927e23624b22ad55235f2239cfa44fd10428eecbeba6d6a717718"
 
+[[package]]
+name = "futures-macro"
+version = "0.3.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e835b70203e41293343137df5c0664546da5745f82ec9b84d40be8336958447b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "futures-sink"
 version = "0.3.32"
@@ -892,8 +918,10 @@ version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "389ca41296e6190b48053de0321d02a77f32f8a5d2461dd38762c0593805c6d6"
 dependencies = [
+ "futures-channel",
  "futures-core",
  "futures-io",
+ "futures-macro",
  "futures-sink",
  "futures-task",
  "memchr",
@@ -1862,6 +1890,7 @@ dependencies = [
  "chrono-tz",
  "cron",
  "data-encoding",
+ "futures",
  "hex",
  "hmac",
  "lettre",