Add deterministic casing and spoken list semantics

[MarcusJRLee]

Summary

• add typed Style Default, Lowercase Prose, and Strict Lowercase policies
• make explicit bullet commands and confident spoken list intent deterministic
• share casing and list semantics with the portable iOS core
• record ADR 0053 and update canonical behavior docs

Verification

• TDD regression suites for casing, list intent, spoken-edit replay, controller fallback, History reformatting, preferences migration, and iOS document pipeline
• full macOS and iOS checks passed before branch extraction
• rebased cleanly onto current main