feat: opt-in by sync.json + per-instance ULID + restic subpath

Reshapes the launcher integration around two ideas:

  1. ONE global Prism PreLaunch/PostExit hook is enough for all
     instances. Wire it once at Settings > Default > Custom commands:

         python /opt/cloud-sync.pyz pull --pack-folder=$INST_MC_DIR
         python /opt/cloud-sync.pyz push --pack-folder=$INST_MC_DIR

     Instances WITHOUT .cloud-sync/sync.json are silent no-ops (rc=0,
     no UI, no banner). The opt-in probe runs BEFORE the UI factory
     so Prism's launch log stays clean for non-sync instances.

  2. Per-instance opt-in via 'setup' / 'init' subcommands that mint a
     fresh ULID-style instance_id + write sync.json (mode 644) and
     token (mode 600). 'disable' removes sync.json; cloud data
     untouched.

Restic URL gains an /<instance_id>/ subpath under the user's
namespace, so two Prism instances of the same Discord user no longer
share a snapshot timeline. --private-repos still gates on the first
path segment (the username); deeper segments are user-controlled,
so this works without server-side coordination. First-push-on-a-new-
instance probes via 'restic cat config' and 'init's the per-instance
repo if absent.

UI label resolution is runtime-only (NEVER stored in sync.json) so
the user renaming the Prism instance just propagates through on
next launch:

    --instance-label  >  $INST_NAME  >  $INST_ID  >  instance_id[:8]

Schema bumps:
  state.json schema: 1 -> 2, adds instance_id field. Schema-1 files
  are treated as missing (existing test1 user re-pulls fresh).
  sync.json schema: 1 (new file).

CLI rework:
  pull / push   no --url; load everything from sync.json
  setup         interactive: Qt login dialog for token; URL prompt
                if --url omitted; falls back to stdin when headless
  init          non-interactive setup; for scripted callers
  disable       rm sync.json

Args dataclass: drops 'url', adds 'instance_label'. cli.parse() now
returns (cmd, Namespace); a separate args_from(ns) builds the Args
so each subcommand can pluck the bits it needs from the Namespace
without forcing a 'one Args fits all subcommands' shape.

73 tests green; pyz 75 KB.

Smoke-verified locally:
  - pull/push on a folder without sync.json: silent rc=0, no banner
  - init writes sync.json (644) + token (600) with correct contents
  - disable removes sync.json, keeps token
  - mint produces unique 26-char base32 instance_ids
  - label resolution chain (flag > INST_NAME > INST_ID > prefix)

tests/test_cli.py

@@ -1,63 +1,102 @@
-"""CLI parsing tests — argv → (subcommand, Args)."""
+"""CLI parsing tests — argv → (subcommand, Namespace) and → Args."""
 
 from __future__ import annotations
 
 import pytest
 
-from cloud_sync.cli import Args, parse
+from cloud_sync.cli import Args, args_from, parse
 
 
-def test_parses_pull_with_required_url() -> None:
-    cmd, args = parse(["pull", "--url=https://cloud.tm.center"])
+# ---- pull / push ----
+
+
+def test_parses_pull_without_url() -> None:
+    """url is sync.json's job now — pull/push don't take --url."""
+    cmd, ns = parse(["pull"])
     assert cmd == "pull"
+    args = args_from(ns)
     assert isinstance(args, Args)
-    assert args.url == "https://cloud.tm.center"
     assert args.allow_download is True
     assert args.headless is False
+    assert args.instance_label is None
 
 
 def test_default_token_file_under_pack_folder() -> None:
-    _, args = parse(["pull", "--url=https://x", "--pack-folder=/tmp/inst"])
+    _, ns = parse(["pull", "--pack-folder=/tmp/inst"])
+    args = args_from(ns)
     assert args.token_file.as_posix().endswith(".cloud-sync/token")
     assert "/tmp/inst" in args.token_file.as_posix()
 
 
 def test_custom_token_file_overrides_default() -> None:
-    _, args = parse(
-        ["pull", "--url=https://x", "--pack-folder=/tmp/inst",
-         "--token-file=/etc/cloud-creds"]
-    )
+    _, ns = parse([
+        "pull", "--pack-folder=/tmp/inst", "--token-file=/etc/cloud-creds",
+    ])
+    args = args_from(ns)
     assert args.token_file.as_posix() == "/etc/cloud-creds"
 
 
 def test_inline_and_space_separated_both_work() -> None:
-    _, a1 = parse(["pull", "--url=https://x", "--pack-folder=/srv"])
-    _, a2 = parse(["pull", "--url", "https://x", "--pack-folder", "/srv"])
-    assert a1.url == a2.url
+    _, ns1 = parse(["pull", "--pack-folder=/srv"])
+    _, ns2 = parse(["pull", "--pack-folder", "/srv"])
+    a1, a2 = args_from(ns1), args_from(ns2)
     assert a1.pack_folder == a2.pack_folder
 
 
 def test_no_gui_flag() -> None:
-    _, a = parse(["push", "--url=https://x", "-g"])
-    assert a.headless is True
-    _, b = parse(["push", "--url=https://x", "--no-gui"])
-    assert b.headless is True
+    _, a = parse(["push", "-g"])
+    assert args_from(a).headless is True
+    _, b = parse(["push", "--no-gui"])
+    assert args_from(b).headless is True
 
 
 def test_no_download_flag() -> None:
-    _, a = parse(["push", "--url=https://x", "--no-download"])
-    assert a.allow_download is False
+    _, ns = parse(["push", "--no-download"])
+    assert args_from(ns).allow_download is False
 
 
 def test_restic_binary_override() -> None:
-    _, a = parse(["push", "--url=https://x", "--restic-binary=/opt/restic"])
+    _, ns = parse(["push", "--restic-binary=/opt/restic"])
+    a = args_from(ns)
     assert a.restic_binary is not None
     assert a.restic_binary.as_posix() == "/opt/restic"
 
 
-def test_missing_url_exits() -> None:
+def test_instance_label_override() -> None:
+    _, ns = parse(["pull", "--instance-label=Frazaserver 1.21.4"])
+    assert args_from(ns).instance_label == "Frazaserver 1.21.4"
+
+
+def test_pack_folder_is_resolved_to_absolute() -> None:
+    _, ns = parse(["pull", "--pack-folder=."])
+    assert args_from(ns).pack_folder.is_absolute()
+
+
+# ---- setup / init / disable ----
+
+
+def test_setup_subcommand_accepts_optional_url() -> None:
+    cmd, ns = parse(["setup", "--url=https://x"])
+    assert cmd == "setup"
+    assert ns.url == "https://x"
+
+
+def test_init_requires_url() -> None:
     with pytest.raises(SystemExit):
-        parse(["pull"])
+        parse(["init"])
+
+
+def test_init_accepts_url_and_token() -> None:
+    cmd, ns = parse(["init", "--url=https://x", "--token=42:secret"])
+    assert cmd == "init"
+    assert ns.url == "https://x"
+    assert ns.token == "42:secret"
+
+
+def test_disable_subcommand_parses() -> None:
+    cmd, ns = parse(["disable", "--pack-folder=/tmp/x"])
+    assert cmd == "disable"
+    assert str(ns.pack_folder) == "/tmp/x"
 
 
 def test_missing_subcommand_exits() -> None:
@@ -67,9 +106,4 @@ def test_missing_subcommand_exits() -> None:
 
 def test_unknown_subcommand_exits() -> None:
     with pytest.raises(SystemExit):
-        parse(["bogus", "--url=https://x"])
-
-
-def test_pack_folder_is_resolved_to_absolute() -> None:
-    _, a = parse(["pull", "--url=https://x", "--pack-folder=."])
-    assert a.pack_folder.is_absolute()
+        parse(["bogus"])