fix: restore web terminal multiline paste by reverting scrollback to 10000

- Revert xterm.js scrollback from 0 to 10000; empirical correlation with
  bracketed-paste mode failing (each line submitted as separate command).
- Add temporary browser-console diagnostics to confirm whether xterm receives
  pi's \e[?2004h enable sequence and whether outbound paste is BPM-wrapped.
- Keep CSS scrollbar hiding and wheel-sensitivity 0 so the original scroll-jank
  fix remains effective.

Typecheck: passed (apps/web)

apps/.pi-map.md

@@ -4,10 +4,10 @@ dir: apps
 index: apps/.pi-map.index.md
 
 ## role
-Contains the main application entry points and executable modules for the project.
+Package apps
 ## files
 ## arch
-Modular application structure with separate deployable units, likely following microservices or multi-app monorepo pattern.
+Contains 0 files.
 ## tags
 -
 ## symbols