{
  "intent": "Split scripts/lib/common.sh, the library 49 scripts source, without changing a single name it exports.",
  "scope": [
    "linux_configuration/scripts/lib/common.sh (620 -> 163)",
    "lib/common_packages.sh, common_services.sh, common_datetime.sh (new)",
    "Non-goal: no behaviour change, no change to the public surface"
  ],
  "changes": [
    "common.sh stays the single entry point and now sources its own three parts, exactly the shape the handoff prescribes for phone_focus_mode/config.sh. All 49 consumers keep sourcing one path and need no edit.",
    "Split by concern: user/root/setup helpers stay, focus-app detection and package installation go to common_packages.sh, service control and the log_* family to common_services.sh, and the date/time/uptime helpers to common_datetime.sh.",
    "The FOCUS_APPS_WINDOWS and FOCUS_APPS_PROCESSES arrays moved with is_focus_app_running, the only function that reads them - leaving them behind produced two SC2034 warnings."
  ],
  "verification": [
    {
      "command": "source common.sh in a subshell and diff `declare -F` against the same from a detached worktree at HEAD",
      "result": "pass",
      "evidence": "Identical 48-function set before and after. For a library with 49 consumers this is the check that matters: it proves the public surface is unchanged rather than inferring it from a passing lint."
    },
    {
      "command": "source common.sh and print the array lengths",
      "result": "pass",
      "evidence": "WINDOWS=13 PROCESSES=2 - the arrays are populated, so moving them did not break is_focus_app_running."
    },
    {
      "command": "shellcheck -x common.sh and shellcheck on each part",
      "result": "fail then pass",
      "evidence": "Two SC2034 warnings for the arrays left behind; zero after moving them. No suppression added."
    },
    {
      "command": "meta/scripts/verify_shell_split.sh on convert_video.sh, a real consumer",
      "result": "pass",
      "evidence": "'libs sourced, functions defined' - a script that sources common.sh from two directories up still resolves everything through the new chain."
    }
  ],
  "risks": [
    "common.sh is sourced by 49 scripts and by systemd-invoked ones; the function-set diff covers the names, but nothing here executes those 49 scripts. A consumer that relied on a definition ORDER rather than a name would not be caught - the parts are sourced in the original order to keep that safe.",
    "_COMMON_DIR uses ${BASH_SOURCE[0]}, which is required here: common.sh is always sourced, never executed, so $0 would point at the calling script."
  ],
  "rollback": [
    "git revert the commit; common.sh returns to 620 lines and the three parts disappear.",
    "After rollback, re-run the declare -F diff and expect the same 48 functions."
  ]
}