_fetch_bounded_gate.nx

_fetch_bounded_gate.nx -- RES-R7 gate: bounded fetch (timeout + no silent truncation). Proves the nx_fetch_bounded capability with a SOVEREIGN, network-free harness: a sys_pipe2 stands in for any readable fd (socket/TLS/file). Write a body into the pipe's write end, drain it through the new bounded consumer, and assert the contract. REQUIRED CHECKS (each computed from a REAL drain, no fabrication): POS-1 small body fully consumed -> FB_OK, counted==1000 POS-2 >512KB body, NO SILENT TRUNCATION -> FB_OVERFLOW, counted==600000 (explicit code + FULL counted length, never clamped to cap) TIMEOUT stalled read returns in budget -> FB_TIMEOUT, elapsed<1000ms NEG-CTL OLD br_drain on same >512KB body truncates at cap with NO signal -> proves the test can actually detect truncation TAMPER tiny cap on a 1000-byte body -> FB_OVERFLOW, never FB_OK A GREEN requires BOTH (old path truncates, == cap, silently) AND (new path returns FB_OVERFLOW with the full count) AND (timeout returns within budget). If the new consumer ever silently clamped like the old one, POS-2 / TAMPER fail RED. build/placement: harness resolves `_fetch_bounded_gate` -> runtime/_hdl_build/_fetch_bounded_gate.nx (1st match). expect_exit: 0 license_tier: ORIGINAL