Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@meteor/server/api/cleanup.ts`:
- Around line 86-89: The maximumDataAge variable extracted from systemSettings
on line 88 is not validated before being used in cleanup threshold calculations.
Add validation logic to ensure maximumDataAge is a positive finite number before
it is applied to any retention or cleanup math. If the value is invalid (less
than or equal to zero, NaN, or Infinity), either clamp it to a safe minimum
value or fallback to the DEFAULT_MAXIMUM_DATA_AGE constant to prevent unsafe
aggressive purging of recent data across collections.

In `@packages/documentation/docs/user-guide/configuration/sofie-core-settings.md`:
- Line 7: In the opening sentence of the sofie-core-settings.md file, replace
the contraction "it's" with the possessive form "its" in the phrase "configured
at its most basic level". The sentence should read "_Sofie Core_ is
configured at its most basic level using environment variables." where "its"
indicates possession rather than "it is".

In `@packages/shared-lib/src/core/model/StudioSettings.ts`:
- Around line 131-133: The new field `defaultShelfDisplayOptions` added to
`IStudioSettings` in StudioSettings.ts needs to be mapped in the REST conversion
layer to prevent it from being silently dropped in API responses. Add the
mapping for `defaultShelfDisplayOptions` in both the `APIStudioSettingsFrom`
function (which converts to API format) and the `APIStudioSettingsTo` function
(which converts from API format) in the type conversion module to ensure proper
round-trip serialization and deserialization of this setting.

In `@packages/webui/src/client/lib/viewPort.ts`:
- Around line 225-227: The variable followOnAirSegmentsHistory is being used
directly as a loop counter without normalization, but since it can contain
fractional values (like 1.5), this causes the loop to iterate an incorrect
number of times. Before assigning followOnAirSegmentsHistory to the loop counter
variable i, normalize it to a non-negative integer by using Math.floor to remove
any fractional part and ensure it doesn't go below zero.

In `@packages/webui/src/client/ui/SegmentTimeline/TimelineGrid.tsx`:
- Line 46: The new prop defaultDisplayDuration added at line 46 is not being
monitored for changes in the component's update guards. Update the
shouldComponentUpdate method to include defaultDisplayDuration in its prop
comparison logic, and ensure that componentDidUpdate also invalidates the
relevant cache (total duration cache) when defaultDisplayDuration changes. This
will prevent the grid from using stale duration values when this prop is
updated.

In `@packages/webui/src/client/ui/Settings/Studio/Generic.tsx`:
- Around line 511-526: The defaultTimeScale property uses IntInputControl which
truncates decimal values via parseInt, but the property is modeled as a number
that should support decimal precision. Replace IntInputControl with a
FloatInputControl or equivalent numeric control that properly handles and
preserves decimal values when updating the defaultTimeScale key through the
handleUpdate callback.

In `@packages/webui/src/client/ui/Shelf/Shelf.tsx`:
- Around line 600-604: The displayOptions variable assignment in the Shelf
component does not guard against params['display'] being a string array (which
occurs when URL has repeated display parameters). The .split() method will fail
at runtime if params['display'] is an array. Add a type check to handle both
cases: if params['display'] is already an array, use it directly; if it's a
string, call .split(',') on it. Ensure the result is always an array of strings
before assigning to displayOptions, falling back to
studioSettings?.defaultShelfDisplayOptions or DEFAULT_SHELF_DISPLAY_OPTIONS as
needed.