cmux fork: tagged Release builds via `reload.sh --tag X --release` drop the DEV banner but keep the tag identity; a same-tag rebuild quits the running app

Applies to forks of manaflow-ai/cmux. scripts/reload.sh --tag <t> builds Debug, which shows the sidebar 'THIS IS A DEV BUILD' banner (#if DEBUG SidebarDevFooter; it can be toggled off in the Debug menu). --release builds the Release configuration with the SAME tagged identity, 'cmux DEV <t>' / com.cmuxterm.app.debug.<t>, so settings and sessions carry over. It is optimized, the banner is compiled out, and so are the debug.* socket commands. scripts/reloads.sh is different: it uses a separate 'cmux STAGING' identity and always launches the app with open -g. Caution: reload.sh, unless --build-only, quits any running app with the same bundle id (osascript quit, then pkill -KILL). Don't build locally with the tag the user runs day to day; give local builds their own tag. Outside a cmuxterm-hq checkout, also set CMUX_DEV_BACKEND_MODE=local and a cmux-tui manifest URL.