PR #996 - tester-army/e2e

What and why

Validate numeric SDK shards before collection. list({ shard: { index: 1.5, total: 2 } }) currently selects tests, although the matching CLI flag is rejected. Zero, negative, non-finite, unsafe, and out-of-range values can also silently produce an empty or incorrect selection.
Use the existing INVALID_CONFIG classification: both numbers must be positive safe integers, and index must be from 1 through total. JavaScript callers passing shard: null also get this classified error. Valid shards keep their selections and test IDs; emitted TypeScript declarations remain byte-identical, with no nullable API widening.

Ran it locally: yes

The actual built e2e/runner list export and built e2e list CLI ran against real config files and registered test bodies in isolated scratch projects. Listing starts no app, engine or worker, makes no provider call, executes no test body and writes no run report.

Case	main `06bb7265`	this branch
13 invalid numeric SDK shards	Accepted without an error	`INVALID_CONFIG`
Unsharded, first, second, valid empty SDK selection	2, 1, 1, 0 runnable tests	Same counts and IDs
Matching CLI cases	13 rejected with exit 2; four valid selections	Same output and exit codes
Frozen public-barrel integration tests	13 fail, four pass	All 17 pass

Five frozen supplemental owners verify runtime classification and import boundaries. The public API exposes list; a separate test uses the built internal runner to verify its serialized configuration error. Original 17 owners remain unchanged.

Review repair	Published `e1a5ae9`	This revision
JavaScript `list({ shard: null })`	`TypeError`, no classified code	`INVALID_CONFIG`
Built internal runner with null shard	Test-category `ERROR`, exit 1	Configuration `INVALID_CONFIG`, exit 2
Invalid numeric shard	Rejected before config/test imports	Same
Valid first/empty shards	Both modules import; IDs stable; bodies never run	Same
Supplemental native owners	Two null assertions fail, three controls pass	All five pass

Full check and build pass. The unchanged full suite passes: 4,157 tests passed, two skipped, including all 22 frozen owners. The original 34 public SDK/CLI cases remain byte-identical after this repair.
Required canonical browser comparison ran six pairs and 76 tests: outcomes, step sequences and counters match. Wall, suite and action timings are classified the same; one individual step remains unresolved. This is a behavior check, with no performance improvement claimed.
This fixes invalid SDK selection. Current signed head: cf6a71d56510d8752c6ffce845677712f00962a6; its upstream CI is pending. The earlier e1a5ae9 checks do not qualify that future head.