fix: extend tool argument normalization to all tools and harden edge cases

- Extend STRING_ARGUMENT_TOOL_FIELDS to normalize Read, Write, Edit,
  Glob, and Grep plain-string arguments (fixes "Invalid tool parameters"
  errors reported by VennDev)
- Normalize streaming Bash args regardless of finish_reason, not only
  when finish_reason is 'tool_calls'
- Broaden isLikelyStructuredObjectLiteral to catch malformed object-shaped
  strings like {command:"pwd"} and {'command':'pwd'} (fixes CR2 from
  Vasanthdev2004)
- Apply blank/object-literal guard to all tools, not just Bash
- Extract duplicated JSON repair suffix combinations into shared constant
- Add 32 isolated unit tests for toolArgumentNormalization

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/services/api/openaiShim.test.ts

@@ -1420,7 +1420,7 @@ test('does not normalize incomplete streamed Bash commands when finish_reason is
     .map(event => (event.delta as Record<string, unknown>).partial_json)
     .join('')
 
-  expect(streamedInput).toBe('rg --fi')
+  expect(streamedInput).toBe('{"command":"rg --fi"}')
 })
 
 test('does not repair truncated Bash objects that do not contain command', async () => {