fix: audit fixes for generated output

[ducdmdev]

Summary

• H1: Exclude test-mode-provider from per-tag index.ts in split mode (was causing broken imports)
• H2: Return numeric timestamp for date-named fields with number type (was emitting ISO strings for terminationDate: number)
• M1: Produce union types (string | boolean) for anyOf with multiple distinct types (was degrading to unknown)
• M2: Skip version segments (v1, v2) when generating operation IDs (was producing getByQueryV2 instead of getByQuerySdkrw)
• M4: Extract shared api-fetch.ts in split mode to avoid duplicating apiFetch in every per-tag hooks.ts

Test plan

• 60 tests pass (4 new tests added, up from 56)
• bun run typecheck clean
• bun run build clean