Add optional automatic SKIE StateFlow discovery

[sonmbol]

Goal

Add optional build-time discovery of public SKIE StateFlow properties so generated Kotlin ViewModels can use native-looking SwiftUI declarations without repeating state key paths.

Scope

• Generate KMPAutomaticallyObservable conformances from the compiled KMP framework symbol graph.
• Support no-state KMPStateObject and KMPObservedObject declarations for generated conformances.
• Preserve all explicit state:, states:, and adapter APIs when generation is not enabled.
• Prevent empty explicit state lists from silently creating an unobserved model.
• Integrate the generated source into the DailyPulse Xcode navigator and Compile Sources phase.
• Declare the generated file as a Run Script output and fail the build when Gradle or generation fails.
• Document setup, limitations, and manual fallback behavior.
• Verify clean-checkout generation and both wrapper types.

Acceptance criteria

• A missing generated file is created before Swift compilation on a clean build.
• The generated folder/file is referenced by the Xcode project and application target.
• @KMPStateObject private var model = Model() works for generated SKIE conformances.
• KMPObservedObject(wrappedValue: model) works for generated SKIE conformances.
• Explicit observation remains fully functional without running the generator.
• Package tests and the DailyPulse simulator build pass.

[sonmbol]

Implemented in PR #3 with automatic Xcode registration. The developer adds only the Run Script; the generator creates the directory/file, adds the Xcode groups and file reference, and inserts the source into the selected target's Compile Sources phase. Registration is idempotent and restores removed membership without duplicates.

The initial registration deliberately requests one additional build because Xcode plans Swift inputs before Run Scripts execute. Later builds update the generated source without rewriting project.pbxproj.

[sonmbol]

Correction: the automatic project-file registration experiment was rejected and has been fully reverted in commit 206d903. PR #3 no longer adds XcodeProj, edits project.pbxproj, or claims automatic target registration. The issue remains open while we look for a same-build solution that does not mutate the Xcode project.