cronr: recurring/one-shot jobs as systemd user timers

add (schedule validated by systemd-analyze, units + script printed),
list (next elapse + last result), run, logs, rm. Command stored as a
script so quoting never meets ExecStart; PATH includes ~/.local/bin
so agent tools resolve. cronr-* namespace guards foreign units.
Smoked live: add -> run -> journal -> rm. Spec: doc/tool-parity.md 3.1.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011KikHkfCiC3yELbsMN8fT9

cronr/README.md

@@ -0,0 +1,54 @@
+# cronr — agent scheduling via systemd user timers
+
+Lets an agent create recurring or one-shot jobs that **survive session
+exit and reboot** — what agy's in-memory `schedule` tool and Claude's
+in-session wakeups cannot do. No daemon: systemd runs the jobs, cronr
+just manages namespaced `cronr-<name>` units. Closes the
+`CronCreate/List/Delete` gap from
+[`doc/tool-parity.md`](../doc/tool-parity.md) §3.1.
+
+## Usage
+
+```
+cronr add <name> --schedule "OnCalendar spec" --cmd "shell command"
+cronr add <name> --at "YYYY-MM-DD HH:MM" --cmd "shell command"   # one-shot
+cronr list                    # schedule, next run, last result per job
+cronr run <name>              # run the job right now (timer untouched)
+cronr logs <name> [--lines N] # the job's journal
+cronr rm <name>               # disable and delete
+```
+
+Examples:
+
+```bash
+cronr add nightly-ci --schedule "*-*-* 07:00" --cmd 'agy -p "check CI status and notify"'
+cronr add backup-ping --schedule "Mon *-*-* 09:00" --cmd 'notifyr send --msg "weekly backup check"'
+cronr add once --at "2026-08-10 03:00" --cmd 'systemctl --user restart helmd'
+```
+
+## How it works
+
+`add` writes three files and prints all of them, so the result is
+fully verifiable:
+
+- `~/.local/share/cronr/<name>.sh` — the command, verbatim (shell
+  quoting never meets systemd's ExecStart parsing)
+- `~/.config/systemd/user/cronr-<name>.service` — oneshot, with
+  `~/.local/bin` on PATH so agent tools (notifyr, svgc, agy…) resolve
+- `~/.config/systemd/user/cronr-<name>.timer` — `OnCalendar=…`,
+  `Persistent=true` for recurring jobs (missed runs fire on next boot)
+
+Schedules are validated by `systemd-analyze calendar` before anything
+is written — you get systemd's own error text plus the computed next
+elapse. `list`/`rm` only ever see `cronr-*` units, so other services
+are untouchable by construction.
+
+`cronr run <name>` starts the service immediately — handy for testing
+a job before trusting the schedule.
+
+## Build & test
+
+```bash
+go test ./...
+go build -o build/cronr .
+```