Add configurable file read limits to SDK tools

[tombee]

Problem

When using the Conductor SDK's file read tool in an agentic context, there's no way to limit how much of a file is read. Large files can:

• Exhaust the context window
• Increase token costs unnecessarily
• Slow down agent iterations

Concrete example from foreman: The implementing stage reads source files during code analysis. A 10,000 line file consumes excessive tokens when only the first 500 lines are relevant.

Proposal

Add configurable line limits to file read operations:

// Option 1: Tool-level configuration
tool := sdk.FileReadTool(sdk.WithMaxLines(500))

// Option 2: Per-call parameter in tool schema
{
  "name": "read",
  "parameters": {
    "path": "/path/to/file.ts",
    "max_lines": 500,      // Optional, default unlimited
    "offset": 0            // Optional, start from line N
  }
}

General Utility

1. Code analysis agents - Any agent reading source files benefits from bounded reads
2. Log analysis - Reading recent log entries without loading entire files
3. Document processing - Preview/summary workflows that only need file headers

Acceptance Criteria

• File read tool accepts optional max_lines parameter
• File read tool accepts optional offset parameter
• When limit is set, output includes indicator that file was truncated
• Default behavior unchanged (read entire file if no limit)
• Unit tests for truncation behavior

Priority

High / Blocking - Foreman implementation blocked until this lands.

Labels

enhancement, sdk, priority:high