fix(content): move lifecycle-transition notes off quick_context into markers

The structure-everything sweep found four more writers packing key:value soup
into quick_context (the human ResumptionNote field), same anti-pattern as the
already-fixed approve_and_start_notes:
  - _record_completion_notes  -> completion_notes:<text>
  - escalate_to_ceo           -> escalation_notes:<text>
  - ceo_approve               -> ceo_approval_notes:<text>
  - ceo_reject                -> ceo_rejection:<reason>

Route them through a unified orchestration_markers['transition_notes'] dict
(keyed by event) via markers.set_transition_note, so quick_context carries only
the structured ResumptionNote and the panel never shows raw <event>:<text> soup.
Adds the typed accessor + a roundtrip test.

tests/unit/foundation/policy/content/test_markers.py

@@ -68,6 +68,17 @@ def test_approve_and_start_notes_roundtrip() -> None:
     assert m.get_approve_and_start_notes(t) == "Board approved; build it."
 
 
+def test_transition_note_roundtrip_keyed_by_event() -> None:
+    t = _task()
+    assert m.get_transition_note(t, "ceo_rejection") is None
+    m.set_transition_note(t, "completion", "Reviewed and merged.")
+    m.set_transition_note(t, "ceo_rejection", "Needs the migration first.")
+    # Each event keeps its own note; setting one doesn't clobber another.
+    assert m.get_transition_note(t, "completion") == "Reviewed and merged."
+    assert m.get_transition_note(t, "ceo_rejection") == "Needs the migration first."
+    assert m.get_transition_note(t, "never_set") is None
+
+
 def test_documenter_self_heal_head_supersede() -> None:
     t = _task()
     m.set_documenter(t, "doc-uuid")