ci(unity-tests): include MCPForUnity/Runtime/** in trigger paths (#1108)

Both the push and pull_request_target paths filters listed
MCPForUnity/Editor/** but not Runtime/, so a PR (or push) that
modified only files under MCPForUnity/Runtime/** would not trigger
Unity tests at all -- including the safe-to-test label flow on a
fork PR. CodeRabbit flagged this as a Low/💤 nitpick on #1103;
PR #1106 made it a concrete recurrence: applying safe-to-test had
no effect because the Runtime-only diff was filtered out.

Adding Runtime/** mirrors the asmdef layout (Editor and Runtime
are the two assembly roots whose code can break Unity compilation),
matches the codebase's "domain symmetry" convention, and closes the
silent-skip path the label gate was designed to prevent.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: dsarno

.github/workflows/unity-tests.yml

@@ -14,6 +14,7 @@ on:
     paths:
       - TestProjects/UnityMCPTests/**
       - MCPForUnity/Editor/**
+      - MCPForUnity/Runtime/**
       - .github/workflows/unity-tests.yml
   # Fork PRs: maintainer applies the 'safe-to-test' label after reviewing
   # the diff. The workflow runs with UNITY_LICENSE in scope against the
@@ -25,6 +26,7 @@ on:
     paths:
       - TestProjects/UnityMCPTests/**
       - MCPForUnity/Editor/**
+      - MCPForUnity/Runtime/**
       - .github/workflows/unity-tests.yml
 
 jobs: