feat: comprehensive Swift ecosystem support (test, package, run, lint)

Context

RTK has minimal Swift support — only swift build has a TOML filter (swift-build.toml), and swift test was just added to the rewrite rules (#767) but has no output filter.

Swift developers use many more commands daily that would benefit from RTK filtering.

Scope

Command	Output type	Filter approach	Expected savings
swift test	Test results (pass/fail, timing, assertions)	TOML or Rust — strip passing tests, show failures only	80-90%
swift test --parallel	Parallel test output	Same as above	80-90%
swift test --filter	Filtered test subset	Same as above	70-80%
swift package resolve	Dependency resolution (Fetching/Resolving lines)	TOML — strip Fetching/Resolving noise	80-90%
swift package update	Package update output	TOML — strip noise, show summary	80-90%
swift run	Build + run output	TOML — strip Compiling/Linking, show app output	70-80%
swiftlint	Linter violations	TOML or Rust — group by rule/severity	70-85%
swiftformat	Formatter output	TOML — files changed summary	70-80%
xcodebuild test	Xcode test output (very verbose)	Rust — complex output, failures only	90-95%
xcodebuild build	Xcode build output	Already has xcodebuild.toml — verify coverage	80-90%

Current state

What	Status
swift build filter	TOML swift-build.toml
swift test rewrite	PR #767 (approved)
swift test filter	Missing
swift package	Missing
swift run	Missing
swiftlint	Missing
swiftformat	Missing
xcodebuild build filter	TOML xcodebuild.toml
xcodebuild test filter	Missing

Implementation

Most commands can be TOML filters (simple pattern stripping). swift test and xcodebuild test may need Rust modules for structured test output parsing (failures only, timing).

Rewrite rules to add

swift package resolve → rtk swift package resolve
swift package update → rtk swift package update
swift run → rtk swift run
swiftlint → rtk swiftlint
swiftformat → rtk swiftformat

References

• Existing filter: src/filters/swift-build.toml
• Existing filter: src/filters/xcodebuild.toml
• PR #767: swift test rewrite rule
• Issue #765: original swift test request