Task: Name compass claude's systemd scope after the environment identity

`compass claude` launches Claude Code in a transient systemd –user scope named claude-<pid>, under app-claude.slice. This isolates it from emacs.service for oomd purposes, but every scope looks identical in systemd-cgtop --user / systemctl --user status — there is no way to tell which worktree/environment a given Claude session belongs to short of cross-referencing PIDs.

Include the environment identity (ORES_ENV_NAME from the checkout's .env, falling back to the checkout directory name) in the unit name, e.g. claude-brave_hopper-<pid>, and in the scope's --description.

• The scope/unit name includes the environment identity (ORES_ENV_NAME, falling back to the checkout directory name), sanitised to the characters systemd unit names allow.
• The --description passed to systemd-run also carries the environment identity alongside the pid.
• Falls back sanely when project_root or .env is unavailable.
• No change in behaviour for anyone invoking the plain claude binary directly (this only affects the compass claude launcher).

Added _env_name(project_root) to compass_claude.py: reads ORES_ENV_NAME from the checkout's .env, falls back to the checkout directory's own name, then sanitises to [A-Za-z0-9_.-] (systemd unit name charset). Threaded the result into both --unit and --description of the systemd-run invocation in run().

Manual QA scenarios (scaffolded via compass add test_scenario, run through the QA Validation Runner panel) that verify this task. Link new ones here as they're created; the scenario doc itself links back via its "Verifies task" field.

`compass claude`'s systemd scope/unit is now named claude-<env>-<pid> (e.g. claude-brave_hopper-<pid>) instead of claude-<pid>, with the environment identity also carried in the --description. Environment identity resolves from ORES_ENV_NAME in .env, falling back to the checkout directory name, sanitised to the characters systemd unit names allow. Verified with unit tests against _env_name() (real .env, missing project_root, missing .env file) and python3 -m py_compile for a clean compile. All acceptance criteria met; no change to the plain claude binary path.