feat: Add support for per-tool rail calls

[JashG]

Description

Adds two capabilities to the LLMRails tool rail pipeline:

• Per-tool rail configuration (per_tool field on tool_output and tool_input): in config.yml, declare which rails apply to which tool. A tool not listed in per_tool receives the global flows only.
• Parallel tool rail execution (parallel: true on tool_output / tool_input): global flows run concurrently using the same _run_flows_in_parallel infrastructure as input and output rails.

The execution of per-tool rails is backed by a new check tool call library rail. This is a library-supplied flow that reduces a per-tool check to a named prompt task — no Colang or Python required from the library consumer. Backed by a check_tool_call action that renders the prompt via llm_task_manager, calls llm_call(), and parses an ALLOW/BLOCK verdict from the model response.

The tool_name is now also included on ActivatedRail. per-tool rails will surface the tool name in the generation log for observability.

Both additions are backward compatible. Configurations without per_tool or parallel: true are unaffected.

Related Issue(s)

Verification

• uv run --locked python qa/validate_tool_call_rails.py: 5 existing tool-rail regression cases, all pass
• uv run --locked python qa/demo_per_tool_rails.py: live end-to-end demo against NVIDIA inference API (requires INFERENCE_API_KEY to be set)

AI Assistance

• No AI tools were used.
• AI tools were used; a human reviewed and can explain every change (tool: Claude Code).

Checklist

• I've read the CONTRIBUTING guidelines.
• This PR links to a triaged issue assigned to me.
• My PR title follows the project commit convention.
• I've updated the documentation if applicable.
• I've added tests if applicable.
• I've noted any verification beyond CI and any checks I couldn't run.
• I did not update generated changelog files manually.
• I addressed all CodeRabbit, Greptile, and other review comments, or replied with why no change is needed.
• @mentions of the person or team responsible for reviewing proposed changes.

[codecov]

Codecov Report

❌ Patch coverage is 89.77273% with 9 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
nemoguardrails/colang/v1_0/runtime/runtime.py	75.00%	5 Missing ⚠️
nemoguardrails/library/tool_call_check/actions.py	92.00%	4 Missing ⚠️

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