chore: upgrade sacp to 11.0.0 stable and agent-client-protocol-schema to 0.11

- Upgrade sacp/sacp-tokio from 11.0.0-alpha.1 to 11.0.0 stable
- Upgrade agent-client-protocol-schema from 0.10 to 0.11
- Rebase vendor/sacp-tokio patches (kill_tree, CREATE_NO_WINDOW, stderr
  truncation) onto official 11.0.0 baseline
- Adapt renamed types: FileSystemCapability → FileSystemCapabilities,
  KillTerminalCommandRequest/Response → KillTerminalRequest/Response

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src-tauri/vendor/sacp-tokio/Cargo.toml.orig

@@ -1,6 +1,6 @@
 [package]
 name = "sacp-tokio"
-version = "11.0.0-alpha.1"
+version = "11.0.0"
 edition = "2024"
 description = "Tokio-based utilities for SACP (Symposium's extensions to ACP)"
 license = "MIT OR Apache-2.0"
@@ -9,7 +9,7 @@ keywords = ["acp", "agent", "protocol", "ai", "tokio"]
 categories = ["development-tools"]
 
 [dependencies]
-sacp = { version = "11.0.0-alpha.1", path = "../sacp" }
+sacp = { version = "11.0.0", path = "../sacp" }
 futures.workspace = true
 
 serde.workspace = true