Bind Python temporal and UUID arguments to their native Go types

[jason810496]

• related: Pass native datetime and UUID literals to stub tasks #71536

Why

Stub annotations already carry temporal and UUID formats, but Go tasks receive the values as strings and must parse them again.

What

Bind each JSON Schema format to its native Go type:

Python annotation	wire format	Go parameter type
datetime, pendulum.DateTime	date-time	time.Time
date	date	time.Time (midnight)
time	time	time.Time (zero date)
timedelta, pendulum.Duration	duration	time.Duration
UUID	uuid	uuid.UUID

// The stub is annotated (when: datetime, window: timedelta, trace_id: UUID)// and called with the formatted strings those annotations imply.funcViaTemporalArgs(
ctx sdk.TIRunContext, log*slog.Logger,
when time.Time, window time.Duration, traceID uuid.UUID,
) (any, error)

• Convert nested slices, maps, and struct fields recursively, with path-aware decode errors.
• Reject incompatible Go types before the task runs. Nullable values require nil-capable types.
• Keep plain string and custom UnmarshalJSON types as escape hatches.
• Parse fixed ISO 8601 durations and reject variable-length year or month components.

Values cross runtimes in JSON form. The example currently passes formatted strings; native Python datetime, timedelta, and UUID call arguments require the separate #71536 Core change.

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Was generative AI tooling used to co-author this PR?

• Yes, with help of Claude Code (Opus 5) and Codex (GPT-5) following the guidelines

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Drafted-by: Codex (GPT-5) (no human review before posting)