Convert Media to Swift

[kean]

Closes #25303

The changes are covered by the extended unit test suite introduced in #25287. I also manually tested it, including the more obscure scenarios that require persisting an error, etc.

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	App Name	Jetpack
	Configuration	Release-Alpha
	Build Number	31150
	Version	PR #25303
	Bundle ID	com.jetpack.alpha
	Commit	ba94b4d
	Installation URL	4b6l5sfb2ds3o

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[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Configuration	Release-Alpha
	Build Number	31150
	Version	PR #25303
	Bundle ID	org.wordpress.alpha
	Commit	ba94b4d
	Installation URL	47d7a95sjl600

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[wpmobilebot]

🤖 Build Failure Analysis

This build has failures. Claude has analyzed them - check the build annotations for details.

[dangermattic]

	1 Warning
⚠️	This PR is larger than 500 lines of changes. Please consider splitting it into smaller PRs for easier and faster reviews.

Generated by 🚫 Danger

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[jkmassel]

Looks ok to me, pretty mechanical changes.

Claude suggested some more test coverage:

**Suggestion: consider adding tests for the remaining untested public API surface (all pre-existing gaps, not regressions from this PR):**

- `willAttemptToUploadLater()` — returns `true` when failure count < `maxAutoUploadFailureCount`, `false` when >=
- `canRetry` — `true` when `absoluteLocalURL` is set, `false` when nil
- `link` — constructs `"{siteURL}/?p={mediaID}"`, returns `""` when blog URL or mediaID is nil
- `remoteStatus` — round-trip through `remoteStatusNumber` to `MediaRemoteStatus` enum
- `absoluteLocalURL` setter with `nil` — verifies setting to nil clears `localURL`
- `fixLocalMediaURLs` with nil content — exercises the `guard var content` early-return path
- `fixLocalMediaURLs` skips remote media — explicitly verifies that the `guard !media.hasRemote` path prevents URL rewriting for uploaded media (currently only tested indirectly via regex not matching `https://`)

I can see the benefit to these, but up to you.

[jkmassel]

This makes sense for absolute paths, but why would we store everything relevant to the documents directory? 🤔