docs(gig): SHOPPING_LIST.md — stage-signal + go-bag purchases for OPAL 2026

Per-item 2-line rationale + 3 example search queries, constrained to few-days Amazon
or a Pigalle scavenge (deadline ~Aug 1). Priority = a USB interface with balanced line
outs (the real fix for "you're too quiet": today FOH is fed from the laptop headphone
jack). Then powered USB hub (LCXL LED stability), a DI-box fallback, a cable/adapter
kit, and an optional passive monitor controller for the fine volume control the KRK
wheel lacks. A sub is noted as post-gig — metering solves the bass blind spot for now.

SHOPPING_LIST.md

+# ParVagues — Shopping List
+
+Gig prep (OPAL 2026, ~J-10). **Delivery reality:** few-days **Amazon**, or **scavenge
+Pigalle** (Paris music shops) — nothing slower than ~Aug 1 is useful.
+Format per item: what & why (2 lines) + 3 example search queries.
+
+## 1. USB audio interface — balanced line outs  ⭐ PRIORITY
+Replaces the laptop headphone-jack feed to FOH with clean balanced TRS/XLR line level:
+lower noise, DI-friendly, proper monitor path. The single biggest stage-signal upgrade.
+- `Focusrite Scarlett 2i2 4th gen`
+- `MOTU M2 audio interface`
+- `Behringer UMC202HD` (budget class-compliant)
+
+## 2. Powered USB hub
+The laptop can't reliably power LCXL + interface + dongles at once; a *powered* hub keeps
+the LaunchControl LEDs from stalling (the urb -32 dropout) and frees ports.
+- `powered USB 3 hub 7 port`
+- `USB hub with power adapter aluminium`
+- `Anker powered USB hub`
+
+## 3. DI box — fallback if no interface in time
+Turns the unbalanced laptop out into a balanced XLR feed for FOH, with a ground-lift to
+kill hum. Cheap insurance so you can gig even without the interface.
+- `passive DI box`
+- `Behringer DI20` (or `DI100` active)
+- `stereo DI box 3.5mm to XLR`
+
+## 4. Cable + adapter kit
+The stuff that ends gigs when it's missing. Carry spares of everything in the chain.
+- `TRS to XLR cable pair 1m`
+- `3.5mm to dual 1/4 TS insert cable`
+- `gaffer tape matte black 50mm`
+
+## 5. Passive monitor controller — the "v60" wish (optional)
+A big smooth volume knob between source and speakers, giving the fine low-level control
+the KRK wheel lacks at the bottom of its range. Nice-to-have, not gig-blocking.
+- `passive monitor controller`
+- `TC Electronic Level Pilot`
+- `Palmer Monicon`
+
+---
+**Later / not for this gig:** a small **sub** would end the "surprised on stage" bass blind
+spot (RP5s roll off ~45-50 Hz) — but for J-10 the fix is low-band **metering** + reference
+tracks, not a purchase. Revisit post-gig.