Giant Questions in Contemporary Physics: A Regime-Based Registry and Classification (IM-K003, v0.1)

This document is part of the Informational Mechanics (IM) framework and is published as a non-authoritative interpretive registry in the IM v0.3 corpus. The paper assembles and classifies a canonical list of “giant questions” in contemporary physics. It provides a structured orientation to which questions are scientifically admissible, which are conceptually unresolved, which are historically resolved yet persist in discourse, and which are inadmissible due to category errors or lack of operator-defined observability. Version 0.3 consolidates IM-K003 as the authoritative reference index for the canonical IM-100 registry.The IM-100 membership remains fixed at 100 questions (no additions or removals). This version introduces a categorized identifier scheme (Qn → -Qn) while preserving canonical numbering. In addition, 23 supplemental questions are included beyond the IM-100 registry to extend structural coverage in quantum measurement, effective-theory structure, and regime-level admissibility analysis. Within the IM-100 set, seven classifications are updated relative to v0.1 (one substantive reclassification; six refinements/strengthening clarifications). The document introduces no new axioms, models, mechanisms, experiments, or physical claims. It is intended as a navigational and clarificatory reference rather than a source of physical results.