feat: add the autorun job runner

Runs the jobs of automation/jobs.yml under one host lock, with load and disk guards, one idle retry on a host misread, artifacts computed twice, explicit-path commits in .cache/autorun/worktree, an opt-in push (--push) and a CI circuit breaker. First jobs: nightly refresh chain, large-files asset dry run, disk cleanup and check, weekly bios integrity. install-timers writes systemd user units without enabling them.

automation/jobs.yml

@@ -0,0 +1,92 @@
+# Jobs scripts/autorun.py runs. A change here is a reviewed commit: the
+# schedule, the gate and the paths a job may commit are all decided here.
+#
+# Commands run in the automation worktree (.cache/autorun/worktree) unless
+# `worktree: false`, which runs them in the main checkout and forbids
+# commits. `python` names the interpreter running autorun.py. A step is a
+# command list, or a mapping with `run`, `ok_codes` and `stdout` (a file
+# the command's output is written to). `twice` recomputes an artifact the
+# gate wrote into `{out}` and compares both, timestamps aside. Each commit
+# takes only the changed files its `paths` globs match, and a job that
+# leaves any other change behind fails. `report` names a JSON file a step
+# writes, kept in the job's status.
+#
+# Schedules are systemd OnCalendar expressions, written into user timers by
+# `python scripts/autorun.py install-timers`.
+
+defaults:
+  min_free_gb: 30
+  max_load_wait: 3600
+  timeout: 21600
+
+jobs:
+  cleanup:
+    schedule: "*-*-* 05:30"
+    worktree: false
+    min_free_gb: 0
+    steps:
+      - [python, scripts/cleanup_disk.py, --apply, --hours, "72"]
+
+  disk-check:
+    schedule: hourly
+    worktree: false
+    lock: false
+    min_free_gb: 0
+    max_load_wait: 0
+    steps:
+      - [python, scripts/cleanup_disk.py, --check]
+
+  nightly:
+    schedule: "*-*-* 02:00"
+    network: true
+    min_free_gb: 120
+    steps:
+      - run: [python, scripts/check_freshness.py, --json]
+        ok_codes: [0, 1]
+        stdout: tmp/autorun/freshness.json
+      - [python, scripts/refresh_stale.py, --findings, tmp/autorun/freshness.json,
+         --only, "data,catalogs"]
+      - [python, -m, scripts.scraper.mame_hash_scraper]
+      - [python, -m, scripts.scraper.fbneo_hash_scraper]
+    gate:
+      - [python, scripts/pipeline.py, --offline]
+    twice:
+      - artifact: database.json
+        run: [python, scripts/generate_db.py, --force, --bios-dir, bios, --output, "{out}"]
+      - artifact: install
+        glob: "*.json"
+        run: [python, scripts/generate_pack.py, --all, --manifest, --offline,
+              --output-dir, "{out}"]
+    commits:
+      - subject: "chore: refresh mame and fbneo hashes"
+        body: >-
+          Written by mame_hash_scraper and fbneo_hash_scraper from the
+          upstream sources, behind a green offline pipeline.
+        paths: [emulators/mame*.yml, emulators/fbneo*.yml]
+      - subject: "chore: refresh romset recipes"
+        body: >-
+          Snapshots refreshed by refresh_stale from the MAME and FBNeo DATs
+          check_freshness reported stale, behind a green offline pipeline.
+        paths: [recipes/*.json]
+      - subject: "chore: regenerate collection records"
+        body: >-
+          Regenerated by the offline pipeline, database.json and the
+          manifests computed twice with the same result.
+        paths: [database.json, install/*.json, install/targets/*.json, README.md,
+                CONTRIBUTING.md, website/src/data/*.json]
+    scratch: [dist, tmp/autorun]
+
+  bios-integrity:
+    schedule: "Sun *-*-* 08:30"
+    worktree: false
+    max_load_wait: 14400
+    steps:
+      - run: [python, scripts/bios_integrity.py, --apply, --json]
+        stdout: tmp/autorun/bios-integrity.json
+    report: tmp/autorun/bios-integrity.json
+
+  assets:
+    schedule: "*-*-* 04:30"
+    network: true
+    steps:
+      - [python, scripts/sync_release_assets.py]