BRO-019: address-bar input — arrow/function keys ERASE the bar, typed UTF-8 is dropped, pasted UTF-8 mojibakes, multi-line paste joins

Now: OPEN
Sev: MED

The pager's key loop (pager.js _feed/_keyCommand) only understands SGR mouse and bracketed-paste escapes; every other escape sequence and every non-ASCII byte is mishandled. Runtime-VERIFIED (headless _feed byte traces), 2026-07-07 audit. The 1-2-byte split-escape leak at the read boundary is already ticketed as a BE-023 bullet (its worst payloads, VERIFIED here: a straddled mouse RELEASE leaks m → mouse tracking silently OFF; a straddled paste-begin leaks the payload → a pasted q QUITS the pager) — fix them together. Method Issues.

Input

Context

CSI leak: arrows/Home/End/Del/PgUp/F-keys arrive as ESC [ … and leak byte-by-byte into key(); in command mode the ESC hits the cancel branch (pager.js:502) and ERASES the whole typed command (VERIFIED: :cat foo + Right-arrow → mode=scroll, cmd=""). In scroll mode the tail bytes hit live bindings by luck of the alphabet.
Alt-keys: terminals send ESC <char>; the ESC is swallowed, the char FIRES its binding (VERIFIED: Alt-q quits).
Typed non-ASCII is dropped (b >= 0x20 && b < 0x7f, pager.js:508): a UTF-8 path char cannot be typed at all. Pasted non-ASCII is kept ONE CHAR PER BYTE via String.fromCharCode (pager.js:774) → Latin-1 mojibake (VERIFIED: paste é → cmd "Ã©"), then double-encoded at render.
Multi-line paste: bytes <0x20 are dropped inside a paste (pager.js:773) — lines silently JOIN into one spell (VERIFIED "abncd" → "abcd"); a paste in scroll mode is swallowed with no message.
No cursor editing (append/backspace only) and _fit tail-truncates a long command, so the edit point can be off-screen — usability, fix opportunistically.

Goals

A CSI/SS3 sequence is consumed WHOLE (parse-and-ignore unknowns); arrows move the bar cursor (or at minimum do nothing); Alt-x never fires x; a 1-2-byte escape tail at the read boundary is carried to the next read (BE-023 leg).
The bar accepts UTF-8: typed and pasted bytes decode identically; a multi-line paste either submits line-by-line or inserts visibly, never silently joins.
Repro tests: byte-level _feed traces per case (the headless driver pattern).

Constraints

views/bro/pager.js _feed/_keyCommand/_keyScroll; keep the C bro's MAUS discipline as the reference; no new bindings/deps.

WIP

Design decisions

(pending) minimal CSI grammar: ESC [ params final + ESC O final, swallow-unknown.

TODOs

Repros: arrow-in-bar, Alt-q, typed é, pasted é, 2-line paste, split-release m, split-paste q.
One escape-sequence reassembler + UTF-8 bar decode; suite green.

Blockers and bummers

None known.

Outcome

(pending)