Add launch hardening gates

docs/NATIVE_V1_SPEC.md

@@ -13,16 +13,17 @@
 >   the default with explicit, visible SSH fallback. Local and Docker benchmark gates
 >   cover cached attach, SSH fallback, and native cold auth (Track C /
 >   `BENCHMARKS.md`).
-> - Milestone 4 — forwarding: **implemented.** Stream mux, `-L`, `-R`, `-D`, `-N`,
->   `-f`, and per-stream flow control exist; terminal-priority/load regressions are
->   covered, and hostile-network/long-soak proof is still being expanded before parity
->   is claimed.
+> - Milestone 4 — forwarding: **implemented with one reliability caveat.** Stream
+>   mux, `-L`, `-R`, `-D`, `-N`, `-f`, and per-stream flow control exist;
+>   terminal-priority/load and replay/reorder regressions are covered. Dropped
+>   `StreamData` recovery still needs stream retransmission before lossy-link
+>   forwarding parity is claimed.
 > - Milestone 5 — hardening: **partly done.** Per-IP token-bucket rate limiting,
->   fail-closed protocol-version checks, parser fuzz targets, fuzz-smoke CI, scripted
->   TUI transport tests, forwarding load/priority tests, and independent persistent
->   session restart tests exist. External review, long soak, and future multi-version
->   compatibility policy are not yet complete. The threat model is published
->   (`docs/THREAT_MODEL.md`).
+>   fail-closed protocol-version checks with a documented v1 policy, parser fuzz
+>   targets, fuzz-smoke/deep CI entry points, scripted TUI transport tests,
+>   forwarding load/priority/replay tests, and independent persistent session restart
+>   tests exist. External review and published long-soak evidence are not yet
+>   complete. The threat model is published (`docs/THREAT_MODEL.md`).
 > - Milestone 6 — workflow parity: **mostly done.** `dosh doctor`, host-trust
 >   management, and the encrypted-key prompt flow exist; cross-OS daily-driver soak is
 >   ongoing.