Near-duplicate comments in json output for agent

### OpenCodeReview Version

v1.8.6 (1b193db35) windows/amd64

### Operating System

Windows

### Installation Method

npm (global)

### LLM Provider

Other OpenAI-compatible endpoint

### Bug Description

`ocr review --to feature-branch --from main --format json --audience agent` will output near-duplicate comments in json
e.g. see log.

### Steps to Reproduce

1. run ocr on code with issues in format=json and audience=agent mode
2. Observe some duplicate comments

### Expected Behavior

- unique comments, even if it costs me an llm call
- An even more problematic side effect is that inline comments in gitlab will be duplicates as well

### Logs / Error Output

```shell
C:\Users\>ocr review --to feature-branch --from main --format json --audience agent
{
"status": "complete",
"message": "Review complete: 8 finding(s) across 9 selected item(s).",
"summary": {
"files_reviewed": 9,
"comments": 8,
"total_tokens": 409739,
"input_tokens": 390776,
"output_tokens": 18963,
"elapsed": "1m16s"
},
"tool_calls": {
"total": 21,
"by_tool": {
"code_comment": 8,
"code_search": 7,
"file_read": 6
}
},
"comments": [
{
"path": "Models/asdf.m",
"content": "The code accesses `config.asdf` before verifying that the `asdf` field exists in `config`. If `config.asdf` is missing, this will raise a runtime error before the later `assert(isfield(config, 'asdf'), ...)` can catch the problem. Add an existence check (e.g., `isfield(config, 'asdf') \u0026\u0026 isfield(config.asdf, 'skip_DB_connection')`) or move the `assert(isfield(config, 'asdf'), ...)` before the conditional.",
"suggestion_code": "if isfield(config, 'asdf') \u0026\u0026 isfield(config.asdf, 'skip_DB_connection') \u0026\u0026 ~config.asdf.skip_DB_connection",
"existing_code": "if ~config.asdf.skip_DB_connection",
"start_line": 20,
"end_line": 20,
"category": "bug",
"severity": "high"
},
{
"path": "Models/asdf.m",
"content": "The code accesses `config.asdf.skip_DB_connection` before confirming the `asdf` field exists, which can cause a runtime error when the field is missing. Move the existence check before the conditional or include an `isfield` guard.",
"suggestion_code": "+if isfield(config, 'asdf') \u0026\u0026 isfield(config.asdf, 'skip_DB_connection') \u0026\u0026 ~config.asdf.skip_DB_connection",
"existing_code": "+if ~config.asdf.skip_DB_connection",
"start_line": 20,
"end_line": 20,
"category": "bug",
"severity": "high"
},
{
"path": "Models/qwertz.m",
"content": "Using ... is clearer and safer.",
"suggestion_code": "for k = 1:numel(blabla)",
"existing_code": "for k = 1:nnz(blabla)",
"start_line": 230,
"end_line": 230,
"category": "style",
"severity": "low"
}
}
...
```

### Additional Context

_No response_

Reproduce the issue with `ocr review --to feature-branch --from main --format json --audience agent` using the command and sample output in the report. Trace how agent findings become JSON comments, then verify that duplicate findings are removed and corresponding GitLab inline comments are unique.

Written by the indexing model from the issue text.