feat: bump minimum deployment target to iOS 15

[andredestro]

Closes RMET-5354.

Why

The library declared iOS 14 as its minimum, which had two consequences:

1. It kept alive four #available(iOS 15, *) checks whose legacy branches used APIs Apple has since deprecated.

2. It hid every deprecation warning from the library's own build. Clang only reports a deprecation when the deployment target is at or above the version where the API was deprecated, so at target 14 the build was clean:

   Deployment target	Warnings
   14.0	0
   18.0	4
   26.0	8

   Those warnings were not invisible to consumers, though. SwiftPM compiles a dependency with the consuming app's deployment target, so an app targeting iOS 18 did see them.

What changed

Minimum target raised to iOS 15 in Package.swift, IONCameraLib.podspec and README.md.

Four #available(iOS 15, *) checks removed. In IONCAMRMediaResultGenerator the legacy branches used AVAsset.duration and AVAsset.tracks(withMediaType:), both deprecated in iOS 16, so deleting the branches also removed those deprecations. The taskOperation / taskiOS14 View extension, already annotated @available(iOS, deprecated: 15.0), is gone in favour of SwiftUI's own task.

AVAsset(url:) → AVURLAsset(url:) in three places. The SDK marks it AVF_DEPRECATED_FOR_SWIFT_ONLY("Use AVURLAsset(url:) instead", ios(4.0, 18.0)). AVURLAsset is available since iOS 4 and is an AVAsset subclass, so no availability check is needed and load(.duration), loadTracks(withMediaType:), load(.isPlayable) and AVAssetImageGenerator(asset:) behave identically.

Video player presentation moved to an @MainActor method. Raising the target makes the DispatchQueue.main.async closure @Sendable, which surfaced a non-Sendable capture of self. Verified this came from the target and not from the other edits: same code builds with 0 warnings at target 14 and 1 warning at target 15. Side effect: playVideo now awaits the presentation instead of firing and returning, which matches the caller in IONCAMRVideoManager already awaiting it.

Deliberately out of scope

• AVAssetImageGenerator.copyCGImage(at:actualTime:) (deprecated in iOS 18). Its replacement, generateCGImageAsynchronously(for:completionHandler:), requires iOS 16, so fixing it now means adding an #available(iOS 16, *) check, i.e. trading a warning for exactly the kind of legacy branch this PR removes. Worth doing when the minimum reaches 16.
• windowScene.interfaceOrientation and the + operator between Text values (both deprecated in iOS 26), for the same reason: their replacements are iOS 26-only.
• swiftformat --lint reports pre-existing violations in 21 of 76 files, including one in a file this PR touches (IONCAMRMediaResultGenerator.swift). Confirmed the same violation exists on main; it comes from a SwiftFormat version drift, not from this change, so it is left alone.

Verification

• xcodebuild build for iOS: 0 warnings, 0 errors
• xcodebuild test on iPhone 17 simulator: 207 tests, 0 failures
• swiftlint --strict: 0 violations

Breaking change

Apps with a deployment target of iOS 14 can no longer consume this library. The commit carries a BREAKING CHANGE: footer, which is what @semantic-release/commit-analyzer reads under the Angular preset to publish 2.0.0. No ! marker in the subject: the Angular preset's headerPattern does not recognise it, so feat!: parses to no type at all and yields no release (details in #20).

[andredestro]

The Validate PR Title check is failing for a reason unrelated to this change: the workflow regex does not allow the ! breaking change marker, so feat!: ... is rejected. Fix is in #20.

Merge order: #20 first, then rebase this branch onto main so the check re-runs against the corrected regex.

Keeping the ! in the title matters here. PRs are squash merged, so the title becomes the commit subject on main and is what semantic-release reads to publish 2.0.0. The commit also carries a BREAKING CHANGE: footer as a second signal, but the title is the one that survives regardless of how the squash description is edited.

[OS-pedrogustavobilro]

Note, when you say "Apps with a deployment target of iOS 14 can no longer consume this library. The commit is marked feat! with a BREAKING CHANGE footer, so semantic-release will publish 2.0.0."

Really it should be feat: (...) with BREAKING CHANGE footer

Without the ! basically. See my other comment #20

[andredestro]

Agreed, dropping the !. Title and commit subject are now feat: bump minimum deployment target to iOS 15, with the BREAKING CHANGE: footer unchanged, which is what produces the major release under the Angular preset. Verified against commit-analyzer@13.0.1: feat: plus footer resolves to major.

Also closed #20. One detail worth recording there: the current preset does not merely ignore !, it fails to parse the header at all, so feat!: alone would have produced no release whatsoever.

The Validate PR Title check should now pass without any workflow change.