feat(immich): multi-time-point scheduling for scheduled/periodic/memory

Replace the single comma-separated text box with an add/remove list of
native HH:MM pickers for the Immich scheduled-assets, periodic-summary,
and memory slots. The backend already stored comma-separated *_times and
scheduled one cron job per time; this makes entering several times per
day discoverable and hardens the read/write path.

Backend:
- services/time_list.py: normalize_time_list (validate / dedup / sort /
  cap at 24, raising TimeListError) + lenient parse_hhmm_list; the
  scheduler now uses the shared parser (drops its private copy).
- tracking_configs API normalizes *_times on every write (422 on bad
  input) and rejects enabling a slot whose times list is empty.
- scheduler warns when an enabled slot has zero or dropped fire times,
  restoring the observability lost with the old per-call warning.

Frontend:
- TimeListEditor.svelte: add/remove native time rows, dedupe + sort on
  emit, per-day cap, collapses on-screen duplicates, aria-labelled rows;
  syncs from the value prop only on external changes (untrack guard) so
  keyboard entry isn't clobbered mid-edit.
- Descriptor-driven save guard: an enabled feature section must have at
  least one time.
- i18n (en/ru) keys; refreshed help text; removed dead invalidTimeList.

Tests: time_list normalization/parsing (incl. non-ASCII/odd shapes) and
the enabled-implies-times validation.

packages/server/tests/test_tracking_config_validation.py

@@ -0,0 +1,114 @@
+"""Tests for the tracking-config write-time guards.
+
+Covers the cross-field rule that an *enabled* Immich dispatch slot
+(periodic / scheduled / memory) must carry at least one fire time — otherwise
+the config saves but the scheduler creates zero cron jobs and the slot is
+silently dead.
+"""
+
+from __future__ import annotations
+
+import pytest
+from fastapi import HTTPException
+
+from notify_bridge_server.api.tracking_configs import (
+    _normalize_time_fields,
+    _validate_enabled_have_times,
+)
+from notify_bridge_server.database.models import TrackingConfig
+
+
+class TestNormalizeTimeFields:
+    def test_normalizes_each_field_in_place(self):
+        values = {
+            "periodic_times": "18:30, 09:00",
+            "scheduled_times": "9:0",
+            "memory_times": "",
+        }
+        _normalize_time_fields(values)
+        assert values["periodic_times"] == "09:00,18:30"
+        assert values["scheduled_times"] == "09:00"
+        assert values["memory_times"] == ""
+
+    def test_ignores_absent_fields(self):
+        values = {"name": "x"}
+        _normalize_time_fields(values)  # no KeyError, no-op
+        assert values == {"name": "x"}
+
+    def test_malformed_raises_422(self):
+        with pytest.raises(HTTPException) as exc:
+            _normalize_time_fields({"scheduled_times": "25:00"})
+        assert exc.value.status_code == 422
+        assert "scheduled_times" in str(exc.value.detail)
+
+
+class TestValidateEnabledHaveTimes:
+    # --- create path (existing=None) ---
+    def test_create_enabled_with_times_ok(self):
+        _validate_enabled_have_times(
+            {"scheduled_enabled": True, "scheduled_times": "09:00"}, None
+        )
+
+    def test_create_enabled_without_times_raises(self):
+        with pytest.raises(HTTPException) as exc:
+            _validate_enabled_have_times(
+                {"scheduled_enabled": True, "scheduled_times": ""}, None
+            )
+        assert exc.value.status_code == 422
+        assert "scheduled_times" in str(exc.value.detail)
+
+    def test_create_disabled_without_times_ok(self):
+        _validate_enabled_have_times(
+            {"memory_enabled": False, "memory_times": ""}, None
+        )
+
+    def test_all_three_kinds_checked(self):
+        for kind in ("periodic", "scheduled", "memory"):
+            with pytest.raises(HTTPException):
+                _validate_enabled_have_times(
+                    {f"{kind}_enabled": True, f"{kind}_times": ""}, None
+                )
+
+    # --- update path (effective state = values merged over existing) ---
+    def test_update_enable_without_providing_times_uses_existing_empty(self):
+        existing = TrackingConfig(provider_type="immich", name="t", scheduled_times="")
+        with pytest.raises(HTTPException):
+            _validate_enabled_have_times({"scheduled_enabled": True}, existing)
+
+    def test_update_enable_with_existing_times_ok(self):
+        existing = TrackingConfig(
+            provider_type="immich", name="t", scheduled_times="09:00"
+        )
+        _validate_enabled_have_times({"scheduled_enabled": True}, existing)
+
+    def test_update_clear_times_while_enabled_in_existing_raises(self):
+        existing = TrackingConfig(
+            provider_type="immich",
+            name="t",
+            scheduled_enabled=True,
+            scheduled_times="09:00",
+        )
+        with pytest.raises(HTTPException):
+            _validate_enabled_have_times({"scheduled_times": ""}, existing)
+
+    def test_update_unrelated_field_does_not_trigger_check(self):
+        # A pre-existing enabled-but-empty config must not block edits that don't
+        # touch the slot's enabled flag or times (only touched kinds are checked).
+        existing = TrackingConfig(
+            provider_type="immich",
+            name="t",
+            scheduled_enabled=True,
+            scheduled_times="",
+        )
+        _validate_enabled_have_times({"name": "renamed"}, existing)
+
+    def test_update_disabling_slot_clears_requirement(self):
+        existing = TrackingConfig(
+            provider_type="immich",
+            name="t",
+            scheduled_enabled=True,
+            scheduled_times="09:00",
+        )
+        _validate_enabled_have_times(
+            {"scheduled_enabled": False, "scheduled_times": ""}, existing
+        )