Enable Hermes tool execution through the copilot-acp adapter by:
- Passing tool schemas and tool_choice into the ACP prompt text
- Instructing ACP backend to emit <tool_call>{...}</tool_call> blocks
- Parsing XML tool-call blocks and bare JSON fallback back into
Hermes-compatible SimpleNamespace tool call objects
- Setting finish_reason='tool_calls' when tool calls are extracted
- Cleaning tool-call markup from response text
Fix duplicate tool call extraction when both XML block and bare JSON
regexes matched the same content (XML blocks now take precedence).
Cherry-picked from PR #4536 by MestreY0d4-Uninter. Stripped heuristic
fallback system (auto-synthesized tool calls from prose) and
Portuguese-language patterns — tool execution should be model-decided,
not heuristic-guessed.