Fix: Support direction TD in Subgraphs

[BambioGaming]

📑 Summary

Fixes a parsing issue where using direction TD inside a subgraph would throw a parse error or be ignored.
This change ensures that subgraph-local directions (TD, BT, RL, LR, etc.) are fully supported in the grammar and properly rendered.

Resolves #6338

📏 Design Decisions

• Updated the flow.jison grammar to allow direction TD and other directions inside subgraphs.

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Build	Status	Details	Updated (UTC)
default (Inspect)	✅ No changes detected	-	Mar 25, 2025, 2:58 PM

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 3.86%. Comparing base (936d107) to head (73db8d8).

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #6415   +/-   ##
=======================================
  Coverage     3.86%   3.86%           
=======================================
  Files          412     411    -1     
  Lines        43189   43178   -11     
  Branches       664     664           
=======================================
  Hits          1670    1670           
+ Misses       41519   41508   -11     

Flag	Coverage Δ
unit	3.86% <ø> (+<0.01%)	⬆️

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see 1 file with indirect coverage changes

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