Add Phase 4 case law: 23 FPSLREB and CIRB labour-board decisions

Ingest the 17 FPSLREB and 6 CIRB decisions that were blocked by Lexum's
Decisia CAPTCHA -- fetched once the volume flag cleared, at a 30s
throttle. The case-law corpus grows from 49 to 72 decisions
(2,444 -> 3,341 chunks); the whole corpus is now 14,078 chunks.
Extends the eval set to 94 questions with 5 labour-board golds.

94-question eval: Hit@1 0.66, Hit@3 0.81, Hit@5 0.91, Hit@10 0.94,
MRR 0.76 -- all 5 labour-board questions retrieve correctly, no
regression on the rest.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

data/eval/questions.json

@@ -87,5 +87,10 @@
   {"query": "When is there no right to appeal a removal order to the Immigration Appeal Division?", "answers": [["IRPA", "64"]]},
   {"query": "Is distributing cannabis an offence?", "answers": [["Cannabis Act", "9"]]},
   {"query": "What is the offence of smuggling goods into Canada under the Customs Act?", "answers": [["Customs Act", "159"]]},
-  {"query": "Is an employee entitled to medical leave under the Canada Labour Code?", "answers": [["Canada Labour Code", "239"]]}
+  {"query": "Is an employee entitled to medical leave under the Canada Labour Code?", "answers": [["Canada Labour Code", "239"]]},
+  {"query": "How should an employer apply progressive discipline to a border services officer?", "answers": [["Menzies", ""]]},
+  {"query": "What is the burden and standard of proof when an employer defends a disciplinary grievance?", "answers": [["Basra (2007)", ""]]},
+  {"query": "What factors determine whether an employer had just cause to discipline or terminate an employee?", "answers": [["Pepper", ""]]},
+  {"query": "What is the test for whether a union breached its duty of fair representation?", "answers": [["McRaeJackson", ""]]},
+  {"query": "Can a union breach the duty of fair representation in how it handles a vaccination-policy grievance?", "answers": [["Watson", ""]]}
 ]