Density Resolution Contract (shared across wave skills)

This skill is the canonical source for the density-aware behaviour every wave skill must implement. Wave skills inherit it by reference and keep a brief inline summary so phrase-grep contract tests stay green; full detail lives here so the same boilerplate is not duplicated six times.

Provenance: feature lean-wave-documentation — D2 (schema-typed sections), D4 (telemetry instrumented day-one), D6 (first-install pedagogical prompt), D10 (one-line expansion descriptions), D12 (rigor cascade), DDD-5 (density resolver shared utility), DDD-6 (telemetry event lives in DES domain).

Output Tiers (per D2 + D10)

Each wave emits a single feature-delta.md whose headings are typed [REF] (always emitted) or [WHY]/[HOW] (lazy expansions). Tier-1 is the always-on baseline; Tier-2 is the lazily-rendered expansion catalog. The .feature file (DISTILL) and other machine artifacts remain the SSOT for executable content; the wave-delta sections are pointers + structured summaries.

• Tier-1 [REF] — emitted under ## Wave: <NAME> / [REF] <Section> headings on every run. Wave-specific list of [REF] sections lives in each wave skill.
• Tier-2 EXPANSION CATALOG — NOT emitted by default. Rendered only when explicitly requested via --expand <id> (DDD-2) or via the wave-end interactive prompt when expansion_prompt = "ask". Each item has a one-line description (per D10) so the menu fits in a single render. Each emitted Tier-2 section is headed ## Wave: <NAME> / [WHY] <Section> or ## Wave: <NAME> / [HOW] <Section>. The catalog itself is wave-specific.

Density resolution (per D12)

Before emitting any Tier-1 section, resolve the active documentation density: