feat: support SDK application tags

[open-swe]

Description

Adds SDK support for passing application_tag / applicationTag through prompt and dataset operations now backed by first-class API handling.

Release Note

Python and JS SDKs now support application tag filtering and assignment for prompts and datasets.

Test Plan

• Added prompt application tag unit coverage for sync and async Python clients.
• Verified changed Python and JS client files with targeted lint/type checks.

Opened collaboratively by liam-langchain and open-swe.

[github-actions]

JS perf benchmark

Lower is better. Noisy on shared runners — treat as a signal, not a gate.

Base64-heavy payload

Single large base64 string per message — the shape the worker-offload path is optimized for.
Payload: 2511.2 KB in / 5.2 KB out, 100 runs.

metric	main	this PR	delta
Wall time (ms)	1922.12	1890.26	-1.7%
createRun total (ms)	85.02	68.58	-19.3%
createRun p50 (ms)	0.58	0.62	+6.4%
createRun p95 (ms)	1.34	0.75	-43.7%
createRun p99 (ms)	28.16	20.86	-25.9%
createRun max (ms)	28.16	20.86	-25.9%
updateRun total (ms)	55.86	38.19	-31.6%
updateRun p95 (ms)	3.19	0.70	-78.1%
loop lag total (ms)	978.67	996.67	+1.8%
loop lag p50 (ms)	0.10	0.11	+3.6%
loop lag p95 (ms)	3.91	4.30	+9.8%
loop lag p99 (ms)	26.77	20.34	-24.0%
loop lag max (ms)	98.50	87.34	-11.3%

Structural payload

Many small strings across a wide/nested object graph. Should bypass worker offload and use sync flush.
Payload: 1239.5 KB in / 13.3 KB out, 100 runs.

metric	main	this PR	delta
Wall time (ms)	1508.33	1572.58	+4.3%
createRun total (ms)	402.10	454.67	+13.1%
createRun p50 (ms)	3.38	3.39	+0.5%
createRun p95 (ms)	5.94	10.82	+82.1%
createRun p99 (ms)	15.62	16.71	+7.0%
createRun max (ms)	15.62	16.71	+7.0%
updateRun total (ms)	29.25	30.93	+5.7%
updateRun p95 (ms)	0.46	0.51	+10.4%
loop lag total (ms)	1052.72	1112.65	+5.7%
loop lag p50 (ms)	0.08	0.07	-7.5%
loop lag p95 (ms)	5.27	5.75	+9.1%
loop lag p99 (ms)	133.63	136.87	+2.4%
loop lag max (ms)	140.82	142.45	+1.2%