Stems are the DEFAULT now: always pre-render, 4-bar runway, rate shown

Paul: "always cache as default — the system has no concept of 'live' so we can always pre-render... cut it to four bars, we have plenty of headroom." The stopped click-hunt agent confirmed the premise: stationary genres are CLEAN (0 clicks); clicks appear during TRAVEL — i.e.

• explorer: ?stems now DEFAULT ON; ?stems=0 is the escape hatch to the byte-identical classic all-live path.

• live.js: the pre-render runway is denominated in CHORD BARS (opts.stemBars, default 4) and computed from live bpm each pass (stemLooka()), replacing the flat ~10s

• the ⬡ readout shows the STEMS rate by default (was only when active, which now means always). CPU ⚡% already always-on.

Verified: headless: default => stems active, readout "⚡13% 1.00× ⬡7:8/8 STEMS 7.0×", 0 errors; ?stems=0 => stem handle null, classic path, 0 errors.

▶ Play it: Mercury Interrogation — where the harmony organ has the least anywhere to hide https://stellate.app/?genre=bebop&seed=7046&path=694.13834,713.13867,675.13867&xdur=13.122

eaf337a https://github.com/aboard-io/stellate/commit/eaf337aefedbb245fca80eeaa6d3b102d04214c9