Preserve supported class entries after unsupported inputs or initial UNSAT

[CaelmBleidd]

A class-wide TypeScript analysis aborted while constructing one callback or BigInt entry input, discarding independently supported methods of the same class. This occurred on original CustomPathedSource, Logging, SpeechToText, and EBMLWriter sources in the fixed 200-class startup smoke. Bot additionally exposed an initial solver UNSAT result treated as a generic failure.

Account for each entry independently. Explicitly reject callback and BigInt input domains that initial-state construction does not model, including aliases and generic upper bounds; retain their method-qualified reasons in unsupportedPaths. Continue constructing and executing other entries without changing the original class surface or denominator. This does not implement callback execution or coerce BigInt to number.

Handle actual solver UNSAT with a narrowly typed initialization exception and retain those entry signatures in the separate additive infeasibleEntryPoints result field. Solver UNKNOWN keeps its existing distinct exception/status path. Unexpected initialization/configuration defects still propagate.

Validation: five new focused startup regressions and five existing shared-analysis checks pass. They include source execution of the supported member, mixed and wholly unsupported entry sets, explicit UNSAT contract checks, and unexpected-error propagation. Disabling the input guard makes the same mixed-entry test fail with the original Expected EtsClassType or EtsUnclearRefType, but got EtsFunctionType diagnostic. Strict usvm-ts main/test Detekt reports zero findings. Full suites are left to CI.

The injected UNSAT tests verify solver-outcome accounting; they do not establish the root cause of the real Bot constraints. Real-corpus startup is rechecked in the integrated smoke run.

Related to #487 and the fixed-corpus startup work.