[refactor](workspace): complete remaining architecture phases

Bundle all pending repository updates, including plugin context de-globalization, runtime hardening, config validation, boundary tests, and supporting docs/scripts.

Co-authored-by: OpenAI Codex <codex@openai.com>
Signed-off-by: Stanislaw Grams <stanislawgrams@gmail.com>

script/dummy-server.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# Run trx-server with the dummy backend for development and testing.
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+
+exec cargo run --manifest-path "$PROJECT_ROOT/Cargo.toml" \
+    -p trx-server -- \
+    --rig dummy \
+    --access serial \
+    "/dev/null 9600" \
+    "$@"