030-release: Prepare clean DPG 0.3.0 core

[sbarbonjr]

• Strengthened context_order="auto" to validate global graph-path support
  against observed execution traces, including longer-history recombinations;
  added a regression test for pairwise-consistent phantom paths.
• Added context-aware DPG construction through context_order in execution
  trace mode. context_order=1 preserves legacy predicate identity; integer
  orders and "auto" split nodes by recent execution history.
• Class outcomes are shared terminal sinks at every context order, and node
  metadata exposes predicate, context, and context_order.
• Added enumeration-free local context-order resolution with explicit
  resolution history and failure reporting.
• Execution-trace edge construction preserves within-case event order and no
  longer applies an unstable sort to the constant case identifier.
• Added exact sklearn decision_path routing. Threshold rounding now formats
  predicate labels without changing the branch selected by the model.
• Added decimal_threshold="auto", which derives precision from the data and
  warns when a tree threshold is off the derived grid.
• Validated the context resolver's optional max_k bound so invalid or
  insufficient caps fail explicitly instead of returning an unresolved order.

[rzfzr]

@sbarbonjr I'm merging this now, I'll manually deploy to pip later.
For the auto-deploy I still have to configure the repo secrets, I'll do this when I have more time so that I can document the process, since we already did the exploratory work once on smx.