feat: add live config profile refresh

- Standardize built-in tool users for shared writable profile mounts
- Mount canonical non-Git profile sources across compatible instances
- Report restart-required outcomes and guard active profile deletion
- Surface restart feedback in config profile editing

Quality gates: frontend build passed; backend py_compile and LSP passed.
Skipped: backend pytest/Ruff unavailable; Docker/manual checks not approved.

tool-images/opencode.dockerfile

@@ -27,8 +27,9 @@ RUN curl -fsSL https://deb.nodesource.com/setup_20.x | bash - \
 # Install OpenCode
 RUN npm install -g opencode
 
-# Create non-root user
-RUN useradd -m -s /bin/bash user
+# Use the shared built-in UID/GID for writable Config Profile mounts.
+RUN groupadd -g 1000 user \
+    && useradd -m -u 1000 -g 1000 -s /bin/bash user
 WORKDIR /home/user
 
 # Set up git