nx_cdmap_interact_gate.nx

nx_cdmap_interact_gate.nx -- referee for the position map's INTERACTION DOOR (datavis DV8 cdp_interact, 2026-09-15). The door is ONE inline script the compare base emits after the 2D cut: hover or focus reveals a mark's values, a legend button toggles a player, dragging brushes a region whose players are listed and whose bounds are written into the URL hash as the trace (cdsel=xlo,xhi,ylo,yhi in permil on the cut axes). This gate drives cdp_interact IN-PROCESS onto a /tmp file and holds the emitted door to its contract: the fit domains and the plot frame it was handed are the numbers in the script (so a brush converts pixels with the same domains the page drew with), the trace key is built from a character code (the lexer forbids '#' and '!' in a literal, and the script must carry neither -- the neg-control counts the bytes), the three interactions are wired, and the trace is re-applied on load. When the live search page is on disk, its door is cross-checked structurally (buttons equal marks inside the cdmap svg, one script, one output), announced through gv_kv and never gv_need. SCOPE STATED: a script executed by a browser is the oracle OUTSIDE the path; this gate proves the door's STRUCTURE and its numbers, never that a browser ran it. license_tier: ORIGINAL