feat(ipc): Error (ru.shturman.Error.*) + well-known имена

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Signed-off-by: Alexander <akotenev2003@gmail.com>

Cargo.toml

@@ -2,7 +2,7 @@
 resolver = "2"
 # Члены растут по планам реализации. crates/core, crates/apps, crates/tools —
 # группировка привилегированного ядра / first-party-апов / dev-инструментов (architecture §3).
-members = ["crates/shturman-common"]
+members = ["crates/shturman-common", "crates/shturman-ipc"]
 
 [workspace.package]
 edition = "2021"