* feat(tooling): enforce noUncheckedIndexedAccess from the base tsconfig
Completes #104600: the flag moves to tsconfig.json, the five per-lane
copies are removed, and test lanes carry one documented opt-out at their
shared parent (the ~4,400 fixture-indexing sites are a tracked
lane-by-lane follow-up). Any future lane inherits the flag by default.
Synthetic probes verify src rejects unchecked reads while test files
compile; all nine lane commands green.
* fix(memory-core): give the batch-call sort a defined element type
Type-aware lint analyzes test files under the base flag (its tsconfig
extends the root, not the test parent), so the widened call[0] made the
bare toSorted() fire require-array-sort-compare.
