#4767: fix(agents): handle read alias required schema

Fixed https://github.com/openclaw/openclaw/issues/2596 and tested. <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR updates `patchToolSchemaForClaudeCompatibility` in `src/agents/pi-tools.read.ts` to better handle tools whose JSON schema `required` list contains only the “original” parameter names (`path`/`oldText`/`newText`) after adding Claude-style aliases (`file_path`/`old_string`/`new_string`). Instead of always emitting `required` when non-empty, it now also *removes* the `required` key entirely when the filtered list becomes empty, preventing schemas with an empty `required: []` from being treated as invalid/overly strict by some consumers. This fits into the tool-wrapper layer that normalizes Claude Code parameter conventions to pi-coding-agent conventions, and patches tool schemas so LLMs trained on Claude Code can call pi tools reliably. <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk. - The change is small and localized to schema-patching logic, preserves existing behavior when `required` remains non-empty, and fixes the specific edge case where an empty `required: []` would otherwise be retained/constructed. No runtime logic outside schema shaping is modified. - No files require special attention <!-- greptile_other_comments_section --> _{(3/5) Reply to the agent's comments like "Can you suggest a fix for this @greptileai?" or ask follow-up questions!} **Context used:** - Context from `dashboard` - CLAUDE.md ([source](https://app.greptile.com/review/custom-context?memory=fd949e91-5c3a-4ab5-90a1-cbe184fd6ce8)) - Context from `dashboard` - AGENTS.md ([source](https://app.greptile.com/review/custom-context?memory=0d0c8278-ef8e-4d6c-ab21-f5527e322f13)) <!-- /greptile_comment -->