fix: extract _repair_tool_call_arguments helper, add tests, bound loop

Follow-up for PR #12252 salvage:
- Extract 75-line inline repair block to _repair_tool_call_arguments()
  module-level helper for testability and readability
- Remove redundant 'import re as _re' (re already imported at line 33)
- Bound the while-True excess-delimiter removal loop to 50 iterations
- Add 17 tests covering all 6 repair stages
- Add sirEven to AUTHOR_MAP in release.py

scripts/release.py

@@ -66,6 +66,8 @@ AUTHOR_MAP = {
     "104278804+Sertug17@users.noreply.github.com": "Sertug17",
     "112503481+caentzminger@users.noreply.github.com": "caentzminger",
     "258577966+voidborne-d@users.noreply.github.com": "voidborne-d",
+    "sir_even@icloud.com": "sirEven",
+    "36056348+sirEven@users.noreply.github.com": "sirEven",
     "70424851+insecurejezza@users.noreply.github.com": "insecurejezza",
     "254021826+dodo-reach@users.noreply.github.com": "dodo-reach",
     "259807879+Bartok9@users.noreply.github.com": "Bartok9",