fix(boot): bake the live-validated prelude into BootTidal.hs — disarm the gF mute-bomb permanently

The problem: `gF1/gF2/gF3` in BootTidal.hs sent a value into `djfbus`, which is
NOT a registered SuperDirt effect. The LCXL faders REST AT 0, so every gF-wrapped
stream shipped an extreme value into a missing bus the moment it was launched —
sound muted mid-set with no way back. Every mature ParVagues track wraps its
streams in gF1/gF2/gF3, so this was armed on essentially the whole set.

It was fixed and live-confirmed on 2026-07-25 ("f123 djfs seem to work great
overall") — but only as a shadow-eval from live/lib/prelude.tidal. That fix lived
in the running ghci and nowhere else: one SuperCollider reboot before OPAL and the
footgun rearmed itself silently. J-10 is the wrong time to depend on remembering
to eval a file.

Approach — three blocks promoted from prelude.tidal into the boot file:

1. SAFE-AT-REST global filters. Swap the phantom djfbus for CORE params that are
   always registered, mapped so fader-rest(0) == BYPASS:
     gHPF = range 20 8000   (rest ⇒ hpf 20, effectively open)
     gLPF = range 20000 180 (rest ⇒ lpf 20k, effectively open)
   gF3 is now literally `id` — a spare fader that cannot touch sound at all.
   Untouched ⇒ no effect, ever. Fader up ⇒ the filter sweeps in. Cannot mute you.

2. DEFAULT-XFADE dN launches. d1-d12 become `xfade N . (|< orbit N-1)`. The orbit
   composition is the load-bearing part: a naive `xfade N` DROPS the orbit that dN
   bakes in, so transitions landed on the wrong LCXL column and the wrong Ardour
   stem. Added an orbit-correct `jumpTo N` for hard cuts. d13-d16 deliberately
   stay plain `p` — orbit 13 is the tidal-ears capture vsink and must not blend.

3. gPanic — the ^93 gate the start_and_midi.scd panic-chord (73+74+91+92) flips.

Validation: type-checked in a throwaway ghci against the real tidal-1.9.5 install.
All signatures resolve as intended — gF1/gF2 :: Pattern ValueMap -> Pattern ValueMap,
gF3 :: a -> a (proving the safe identity), d1 keeps its original
Pattern ValueMap -> IO () shape so no track file needs an edit, d13 stays
ControlPattern -> IO (), jumpTo :: ID -> Pattern ValueMap -> IO ().

prelude.tidal is demoted from "source of truth we forgot to promote" to an
explicit RESCUE SHEET: it now documents the stale-boot symptom (push fader 49,
sound mutes instead of sweeping) and stays evaluable as an in-session hot-patch.
One source of truth, one less thing to remember mid-set.

BootTidal.hs

@@ -114,18 +114,38 @@ let p = streamReplace tidal
     anticipate i = transition tidal True (Sound.Tidal.Transition.anticipate) i
     anticipateIn i t = transition tidal True (Sound.Tidal.Transition.anticipateIn t) i
     forId i t = transition tidal False (Sound.Tidal.Transition.mortalOverlay t) i
-    d1 = p 1 . (|< orbit 0)
-    d2 = p 2 . (|< orbit 1)
-    d3 = p 3 . (|< orbit 2)
-    d4 = p 4 . (|< orbit 3)
-    d5 = p 5 . (|< orbit 4)
-    d6 = p 6 . (|< orbit 5)
-    d7 = p 7 . (|< orbit 6)
-    d8 = p 8 . (|< orbit 7)
-    d9 = p 9 . (|< orbit 8)
-    d10 = p 10 . (|< orbit 9)
-    d11 = p 11 . (|< orbit 10)
-    d12 = p 12 . (|< orbit 11)
+    -- DEFAULT-XFADE track launches (#13).  Every dN crossfades in over 4
+    -- cycles AND keeps its orbit.  The naive `xfade N` LOSES the orbit that
+    -- dN bakes in → sound lands on the wrong LCXL column / Ardour stem, so
+    -- the `(|< orbit N-1)` must stay composed in here.  Fits the livemidi
+    -- model: dN evals are track LAUNCHES, so auto-blend has ~zero downside
+    -- and makes every track→track move clean with no code edit.
+    --   d1 $ <track A>   … later …   d1 $ <track B>   ⇒ B xfades over A.
+    -- For an INSTANT set (fast iteration on one line) use  p N $ …
+    -- For an orbit-correct HARD CUT use  jumpTo N $ …  (below).
+    d1 = xfade 1 . (|< orbit 0)
+    d2 = xfade 2 . (|< orbit 1)
+    d3 = xfade 3 . (|< orbit 2)
+    d4 = xfade 4 . (|< orbit 3)
+    d5 = xfade 5 . (|< orbit 4)
+    d6 = xfade 6 . (|< orbit 5)
+    d7 = xfade 7 . (|< orbit 6)
+    d8 = xfade 8 . (|< orbit 7)
+    d9 = xfade 9 . (|< orbit 8)
+    d10 = xfade 10 . (|< orbit 9)
+    d11 = xfade 11 . (|< orbit 10)
+    d12 = xfade 12 . (|< orbit 11)
+    -- orbit-correct HARD CUT (when you DON'T want the 4-cycle blend)
+    jumpTo i = case i of
+        1  -> jump 1  . (|< orbit 0);   2  -> jump 2  . (|< orbit 1)
+        3  -> jump 3  . (|< orbit 2);   4  -> jump 4  . (|< orbit 3)
+        5  -> jump 5  . (|< orbit 4);   6  -> jump 6  . (|< orbit 5)
+        7  -> jump 7  . (|< orbit 6);   8  -> jump 8  . (|< orbit 7)
+        9  -> jump 9  . (|< orbit 8);   10 -> jump 10 . (|< orbit 9)
+        11 -> jump 11 . (|< orbit 10);  12 -> jump 12 . (|< orbit 11)
+        _  -> p i
+    -- d13-d16 stay plain `p` (no orbit offset): utility/capture streams,
+    -- orbit 13 is the tidal-ears capture vsink — do NOT give these xfade.
     d13 = p 13
     d14 = p 14
     d15 = p 15
@@ -281,10 +301,28 @@ let -- DPV specific parameters
     midiG' ch l h = _gainG (range l h ch)     -- midiGain   control
     midiGdef      = midiG' 1 0 1             -- midiGain   default
     midiG  ch     = midiG' ch 0 1             -- midiGain   default
-    -- Global filters
-    gF1 = (# djfbus 1 (range 0.05 0.95 "^49"))
-    gF2 = (# djfbus 2 (range 0.05 0.95 "^50"))
-    gF3 = (# djfbus 3 (range 0.05 0.95 "^51"))  
+    -- =============================================
+    -- Global filters (#21) — SAFE-AT-REST
+    -- The old form was  gF1 = (# djfbus 1 (range 0.05 0.95 "^49"))  and it
+    -- was a live footgun: `djfbus` is NOT a registered SuperDirt effect, and
+    -- the LCXL fader RESTS AT 0 → every gF-wrapped stream got an extreme
+    -- value into a missing bus → sound muted mid-set with no way back.
+    -- Fix: use CORE params (hpf/lpf, always registered) mapped so that
+    -- REST (fader down = 0) == BYPASS.  Untouched ⇒ no effect, ever.
+    -- Push a fader up ⇒ the filter sweeps in.  Cannot mute you.
+    -- Live-confirmed 2026-07-25 ("f123 djfs seem to work great overall").
+    -- =============================================
+    gHPF ch = (# hpf (range 20 8000 ch))     -- fader up ⇒ high-pass climbs; rest(0)=hpf 20 ≈ open
+    gLPF ch = (# lpf (range 20000 180 ch))   -- fader up ⇒ low-pass closes;  rest(0)=lpf 20k ≈ open
+    gF1 = gHPF "^49"    -- CC49 fader = high-pass build (tension riser)
+    gF2 = gLPF "^50"    -- CC50 fader = low-pass sweep (muffle/drop)
+    gF3 = id            -- CC51 spare, held safe (id = never touches sound)
+    -- PANIC CHORD (#34) — hold LCXL push buttons 73+74+91+92 together; the SC
+    -- bridge (start_and_midi.scd) edge-detects the chord and flips a persistent
+    -- "^93" toggle, echoed on the LCXL LEDs (lit = active).  Tidal side is just
+    -- a plain 0/1 gain gate.  Not applied to any stream by default — wrap it on
+    -- whichever track you're actively composing:  d1 $ gPanic $ gF1 $ …
+    gPanic = (# gain (range 1 0 "^93"))  -- ^93=0 normal, ^93=1 silent
     -- Global masks (defaults)
     gMask = (midiOn "^41" (mask "t!7 f"))
     gMute1 = (midiOn "^73" (mask "f*16"))

live/lib/prelude.tidal

--- ParVagues live prelude — TRY blocks (nucleus of the #23 lib)
--- Open in Pulsar, eval a block (Ctrl-Enter inside the :{ … :}) to try it LIVE.
--- These shadow the BootTidal.hs defs in the running session — no reboot needed.
--- Once a block feels right, we bake it into BootTidal.hs (or load this file at boot).
+-- ParVagues live prelude — RESCUE SHEET (was: TRY blocks, nucleus of the #23 lib)
+--
+-- ✅ ALL THREE BLOCKS BELOW ARE NOW BAKED INTO BootTidal.hs (2026-07-25).
+--    A fresh Tidal boot already has safe gF1/2/3, xfade-dN + jumpTo, and gPanic.
+--    You do NOT need to eval this file in a normal session anymore.
+--
+-- KEEP IT for one reason: it is the hot-patch if you ever find yourself on a
+-- STALE boot mid-set (an old ghci still alive, a machine that didn't pick up
+-- the new BootTidal.hs, a borrowed laptop). Symptom: push fader 49 and the
+-- sound MUTES instead of sweeping ⇒ you're on the old djfbus gF.
+-- Rescue: open this file, Ctrl-Enter inside each :{ … :} block. These shadow
+-- the boot defs in the running session — no reboot, no lost patterns.
+--
+-- BootTidal.hs is the source of truth. If you change a def here, change it
+-- there too, or delete it here.
 
 -- =====================================================================
 -- #21 — SAFE global filters (gF).  The footgun: `djfbus` is NOT a