feat(aura-core): typed construction-arg seam on PrimitiveBuilder

A second, closed construction channel beside the scalar bind seam
(refs #271): ArgKind (Tz / TimeOfDay / Count — deliberately NOT
ScalarKind, which stays invariant 4's streamed set), ArgSpec, ArgValue,
ConstructionArg (verbatim strict-form strings, the id-bearing twin of
BoundParam), ArgOpError, and an ArgsState on PrimitiveBuilder:
pending(name, doc, specs, make) declares an arg-bearing recipe that is
introspectable but not constructible; try_args validates strictly
(exact IANA name, zero-padded HH:MM, plain positive decimal — the
accepted form IS the canonical form, no normalization layer), then
runs make and returns the configured builder. build() on a pending
builder panics — the bind panic-contract twin; the data path always
goes through try_args.

chrono-tz enters aura-core for the typed Tz value (already a workspace
dependency of four crates; typed values at the seam beat a
validated-string re-parse split across two coupled sites).

One test per ArgOpError variant plus strict-form refusal pins.

Cargo.lock

@@ -160,6 +160,7 @@ dependencies = [
  "aura-core",
  "aura-engine",
  "aura-ingest",
+ "aura-market",
  "aura-measurement",
  "aura-registry",
  "aura-research",
@@ -167,6 +168,7 @@ dependencies = [
  "aura-std",
  "aura-strategy",
  "aura-vocabulary",
+ "chrono-tz",
  "clap",
  "data-server",
  "libc",
@@ -192,6 +194,7 @@ dependencies = [
 name = "aura-core"
 version = "0.1.0"
 dependencies = [
+ "chrono-tz",
  "serde",
  "serde_json",
 ]
@@ -307,8 +310,6 @@ dependencies = [
  "aura-backtest",
  "aura-core",
  "aura-strategy",
- "chrono",
- "chrono-tz",
 ]
 
 [[package]]