Accept absent map-level sourcesContent and preserve null source-name slots alongside known originals and aligned content. Represent unnamed local declarations explicitly, retain leaf-local and flattened indices, and preserve declared indexed-section order across consumers.
Account for added indices before browser output allocation. Accept legacy retained rows without indices. Consolidate public CLI/MCP source-map fixtures and update the stale named-source-only assertion.
BREAKING CHANGE: Browser source-map original and mapping rows expose null for unavailable source names instead of inventing an unknown-source string. New index fields are optional when reading older retained evidence.
Refs #2023, #2024