Function build_surface 

pub fn build_surface(
    compiler: &ContextCompiler<'_>,
    request: SurfaceRequest<'_>,
) -> SurfaceRenderResult

THE one authoritative surface pipeline: compile candidates → heterogeneous PPR (global or task) → [pagerank::SystemRanker::project_to_symbols] → per-entry importance (final_importance) → required coverage → MMR diversify → token-aware quotas → soft/hard budget selection → render. Global mode is the historical select_and_render_global pipeline; Task mode adds task PPR (lexical seeds, warm global start), novelty suppression against the ledger, and the same MMR/quotas/selector/render tail. Every surface consumer (production, CLI, MCP, plugin, benchmark ablations) routes through this service — no consumer reimplements ranking. Deterministic and no-panic.