feat: show additional rooms in notes when deduplicating calendar events

[Copilot]

When duplicate calendar entries exist for the same lecture (same summary + start time) but with different room locations, the deduplication was discarding the additional room information entirely.

Changes

• First pass collection: Collect all locations per dedup key before processing
• Preserve additional rooms: Pass non-duplicate locations to cleanEvent and prepend them to the description
• Dedup handling: Use a map to prevent duplicate room names from appearing

Output format

When events are deduplicated with different locations, the description now includes:

Additional rooms:
MI HS 1

https://nav.tum.de/room/5508.02.801
MW 1801, Ernst-Schmidt-Hörsaal (5508.02.801)
...

Original prompt

---

This section details on the original issue you should resolve

<issue_title>multiple rooms in notes</issue_title>
<issue_description>If there are multiple rooms show the other rooms in notes </issue_description>

Comments on the Issue (you are @copilot in this section)

@CommanderStorm Could you provide a screenshot of what event you are refering to? Calendar entrys in TUMonline natively only have one room as far as I have seen @CommanderStorm Could you share the source ical of just these events which we are not deduplicating?

Note that we already have deduplication (=> maybe this is not working perfectly?):

CalendarProxy/internal/app_test.go

Lines 59 to 70 in 01b86ba

	func TestDeduplication(t *testing.T) {
	testData, app := getTestData(t, "duplication.ics")
	calendar, err := app.getCleanedCalendar([]byte(testData))
	if err != nil {
	t.Error(err)
	return
	}
	if len(calendar.Components) != 1 {
	t.Errorf("Calendar should have only 1 entry after deduplication but has %d", len(calendar.Components))
	return
	}
	}

This is the function that does the deduplication (PR welome, if you want to give this a try ^^):

CalendarProxy/internal/app.go

Lines 167 to 194 in 01b86ba

	func (a *App) getCleanedCalendar(all []byte) (*ics.Calendar, error) {
	cal, err := ics.ParseCalendar(strings.NewReader(string(all)))
	if err != nil {
	return nil, err
	}
	// Create map that tracks if we have allready seen a lecture name & datetime (e.g. "lecturexyz-1.2.2024 10:00" -> true)
	hasLecture := make(map[string]bool)
	var newComponents []ics.Component // saves the components we keep because they are not duplicated
	for _, component := range cal.Components {
	switch component.(type) {
	case *ics.VEvent:
	event := component.(*ics.VEvent)
	dedupKey := fmt.Sprintf("%s-%s", event.GetProperty(ics.ComponentPropertySummary).Value, event.GetProperty(ics.ComponentPropertyDtStart))
	if _, ok := hasLecture[dedupKey]; ok {
	continue
	}
	hasLecture[dedupKey] = true // mark event as seen
	a.cleanEvent(event)
	newComponents = append(newComponents, event)
	default: // keep everything that is not an event (metadata etc.)
	newComponents = append(newComponents, component)
	}
	}
	cal.Components = newComponents
	return cal, nil
	}

</comment_new>

• Fixes multiple rooms in notes #158

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