release: v1.14.0 — the worker takes its flags, and can be run as a service

[hakeemRash]

v1.14.0

Merging this pushes v1.14.0 — auto-release.yml fires on a push to main
touching CHANGELOG.md, reads the first versioned heading, tags, builds, and
lands the Homebrew formula bump itself.

Fixed — the worker ignored every flag it was given

hkm worker --queue=mails forwards its arguments verbatim to
app/worker/run.php, which read only WORKER_QUEUE from the environment. The
flag was accepted in silence and the worker drained default: no error, no
warning, a running process, and the wrong queue.

The entry point and the scaffolding template now parse -q/--queue,
-n/--max-iterations, --memory and -h/--help, each overriding the matching
environment variable, and exit 2 on an argument they do not recognise rather
than ignoring it. The environment fallbacks also moved from getenv() to
env(), since the loader injects .env into $_ENV and skips putenv() — so
getenv('WORKER_QUEUE') could not see a value set in the project's .env.

Added — hkm service

Generates the unit that supervises that worker, for whichever manager the host
runs.

hkm service [path|name]          preview — writes nothing
hkm service write                write it to <project>/var/service/
hkm service install [--start]    place it, reload the manager, optionally start
hkm service remove               stop, disable, delete

systemd or launchd (--platform overrides, so a Mac generates the Linux unit it
deploys); --system / --user choose the location, defaulting to system on
Linux and a user agent on macOS. --dry-run (-n) reports every write and
command for the three mutating verbs and performs none of them.

Three things the generated unit gets right that a hand-written one usually does
not:

• ExecStart runs the launcher, hkm worker -p <root>, not php plus an
  absolute vendor/autoload.php — the launcher self-locates the kernel, so an
  upgrade that moves a version-stamped install directory cannot break the queue.
  --exec=php emits the direct form for a server with no launcher, and states
  the pinned autoload's cost in the unit.
• TimeoutStopSec / ExitTimeOut is 90s — the worker traps SIGTERM and
  finishes the job in flight, and launchd's 20s default SIGKILLs it
  mid-transaction.
• PATH and HKM_PHP_BIN are pinned — a service inherits none of a login
  shell's PATH and /opt/homebrew/bin is on neither manager's default. Without
  the pin the only diagnostic is error: FileNotFound, naming nothing. Found by
  running the generated unit, not by reading it.

Values reaching the unit are validated, not interpolated: a queue name may hold
only [A-Za-z0-9._:-]; ExecStart tokens with whitespace are quoted; plist
strings are XML-escaped.

Verified

• Full launchd lifecycle on macOS: preview → write → install → --start →
  launchctl print showing state = running with the process actually draining
  mails → remove, with nothing left behind. plutil -lint accepts the plist.
• The --exec=php ExecStart line run under a stripped env -i with only the
  pinned variables.
• Worker flags: long and short forms, env-only, flag-overrides-env, and the
  unknown-argument rejection.
• zig build, zig build test (13 new unit tests), zig fmt --check.

Not verified: the systemd path could only be rendered and read here — no
Linux host. daemon-reload, enable --now and the sudo copy are unexercised.