docs: the communication stack — /protocol namespace, layered model, non-unix hierarchy, SMEP/SMAP plan

The security-track design set. communication.md is the model: four layers
(namespace / protocol / channel / transport), packets and signals, parties
addressed by the channel and objects by target, transports as replaceable
buffer+doorbell mechanisms. protocol-namespace.md is L3+L2: /protocol names
contracts, resolution establishes a channel, init is the registrar,
restriction is per-process namespace delegation (with the microphone-prompt
worked example), the envelope is the universal packet header, migration
P1-P5 retires ServiceId. file-system-hierarchy.md replaces the unix-FHS
spec with the danos-native tree (/applications, /protocol, /system,
/volumes) and its migration table. ipc.md is re-cut as the kernel-ipc
transport document. smep-smap.md designs the kernel hardening: copy
discipline for the eight raw user-pointer syscalls, then SMEP, then SMAP
as a permanent tripwire.

docs/character-devices-and-tty.md

@@ -38,8 +38,11 @@ So the design is small:
 the existing VFS wire protocol, whose read/write have stream semantics.**
 
 No device numbers, no `/dev` special casing, no new syscalls, no new protocol —
-a service mounts itself at a path (per the FSH, e.g. `/device/console`), clients
-open it with `runtime.fs` like any file, and `FileStatus.kind` says what it is.
+a service is reachable at a path, clients open it with `runtime.fs` like any
+file, and the node kind says what it is. (Since the protocol namespace landed
+in design, that path is `/protocol/console` — a protocol node, see
+[os-development/protocol-namespace.md](os-development/protocol-namespace.md) —
+rather than a mounted device file; the stream semantics below are unchanged.)
 
 ### Stream semantics (the actual contract change)
 
@@ -160,7 +163,12 @@ Phase 1 both list; neither track repeats them.
 - [zig-self-hosting.md](zig-self-hosting.md) — ditto ("stdio as fds").
 - [file-system-development/vfs-protocol.md](file-system-development/vfs-protocol.md) —
   the wire protocol this note extends.
-- [file-system-development/danos-file-system-hierarchy-FSH.md](file-system-development/danos-file-system-hierarchy-FSH.md)
-  — where `/device/console` lives.
+- [file-system-development/file-system-hierarchy.md](file-system-development/file-system-hierarchy.md)
+  — the tree the console surfaces in.
+- [os-development/protocol-namespace.md](os-development/protocol-namespace.md) —
+  supersedes this note's device-node naming: the console lands as a protocol
+  (`/protocol/console`, a protocol node), not a `/dev`-style device file. The
+  stream semantics designed here (line discipline, cooked/raw modes) carry over
+  unchanged.
 - [device-driver-development/input.md](device-driver-development/input.md) — the
   `InputEvent` stream the console cooks.