Enhance State Transition View with attached transitions and pseudostate support

[Malcolmnixon]

This pull request implements comprehensive support for attached state transitions, entry/do/exit actions, and inherited pseudostate features in SysML v2 state machines. It addresses several correctness bugs and limitations in the previous implementation, ensuring that all states and transitions are properly modeled and rendered, including those using common SysML idioms such as implicit transition sources (start, done) and attached transitions. The changes span the AST builder, reference resolver, and layout strategy, and update both code and documentation to reflect the new behavior.

State Machine Modeling and AST Construction:

• AstBuilder now supports attached transitions (e.g., state X; accept ... then Y;) and entry/do/exit action features by introducing explicit visitor methods for these grammar constructs. This ensures all states and transitions are captured in the AST, including those with implicit or inherited sources. [1] [2]
• Entry/do/exit actions are minimally modeled as resolvable features, allowing references to them from transitions.

Reference Resolution Improvements:

• ReferenceResolver now resolves transition sources via a new ResolveTransitionSource method, which first tries regular feature-chain resolution, then falls back to a dedicated inherited-member lookup for start/done and entry-action features. This resolves previously unresolvable transitions that use inherited pseudostate features. [1] [2]
• The fallback for inherited pseudostate resolution is intentionally narrow, covering only the standard library's Actions::Action for start/done, consistent with the SysML v2 spec and project roadmap.

Layout and Rendering Logic:

• StateTransitionViewLayoutStrategy now prefers a semantically-resolved initial transition (e.g., from start or an entry action) over the previous first-declared-state heuristic when placing the initial marker. It also excludes pseudostate and entry-action sources from being rendered as state boxes, eliminating spurious boxes for non-state features. [1] [2] [3] [4]

Documentation Updates:

• The roadmap and technical documentation have been updated to describe the new behavior, the rationale for changes, and the limitations of the current implementation. This includes detailed explanations of the new AST visitor logic, reference resolution fallback, and layout strategy adjustments. [1] [2] [3] [4] [5] [6] [7]

Summary of Most Important Changes:

1. State Machine Parsing and AST Construction

• Added explicit handling for attached transitions and entry/do/exit actions in AstBuilder, ensuring all relevant state machine elements are captured and resolvable. [1] [2]

2. Reference Resolution Enhancements

• Implemented ResolveTransitionSource and TryResolveInheritedActionMember in ReferenceResolver to resolve inherited pseudostate features (start/done) and entry-action sources for transitions. [1] [2]

3. Layout and Rendering Improvements

• Updated StateTransitionViewLayoutStrategy to use semantically-resolved initial transitions for marker placement and to exclude pseudostate/entry-action sources from state box rendering. [1] [2] [3] [4]

4. Documentation and Roadmap

• Revised roadmap and technical documentation to reflect new modeling capabilities, rationale, and known limitations. [1] [2] [3] [4] [5] [6] [7]

These changes close several longstanding gaps in SysML v2 state machine support, ensuring correctness and spec compliance for common modeling idioms.