Fix inverted pre_activation logic in thank-you workflow

The workflow was activating for core team members instead of community contributors.
Changed `is_team_member == 'true'` to `is_team_member != 'true'` in pre_activation job.

This fixes the workflow failure where PRs from team members (like #15660 from Jacobjeevan)
were incorrectly triggering the thank-you note generator instead of being skipped.

Added documentation notes in both .md and .lock.yml files to prevent this issue
from being reintroduced during future recompilations with gh-aw.

Co-authored-by: bodhish <14979190+bodhish@users.noreply.github.com>

Author: Claude

.github/workflows/thank-you-note.lock.yml

@@ -15,6 +15,10 @@ safe-outputs:
   add-comment:
     max: 1
     target: "*"
+# NOTE: When compiling this workflow with gh-aw, manually verify that the
+# pre_activation job's activated output uses != 'true' instead of == 'true'
+# to ensure the workflow only runs for NON-team members (community contributors).
+# gh-aw v0.42.13 had a bug that inverted this logic.
 ---
 
 # Thank You Note Generator