feat(scenario): add scenario cli with cli docs

[JasonZ-c]

Description

Adds a new pare scenarios CLI for listing, inspecting split files, validating scenario ID files, and running scenario generation workflows.
Cleans up tooling by moving scenario-runner logic into pare/ and fixing dependency checks for local development.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactoring (code restructuring without changing behavior)
• Documentation update
• Test coverage improvement
• Performance improvement
• Chore (dependency updates, CI/CD, tooling)

Related Issues

Closes #N/A

Related Design Documents

• None

Component

• Core (All files in the root pare, e.g. pare/environment.py)
• Agents (All files in pare/agents/)
• Scenarios (All files in pare/scenarios/)
• Scenario Generator (All files in pare/scenario_generator/)
• Apps (All files in pare/apps/)
• Testing Infrastructure
• Documentation (Documentation files e.g., docs/, mkdocs.yml, README.md)
• Other

Other: CLI / developer tooling

Changes Made

• Added a new pare scenarios CLI module and wired it into the top-level pare command.
• Added CLI coverage for help output, root --list behavior, and split metadata output.
• Moved scenario runner logic into pare/scenarios/run_scenarios.py and kept source code under pare/ independent from scripts/.
• Updated scenario docs under docs/scenarios/ and docs/index.md to reflect the new CLI and current pare naming.
• Updated dependency/tooling config so deptry and local checks pass with the new source layout.

Breaking Changes

• This PR introduces breaking changes
• Migration guide included (if applicable)

Details:

• None.

Testing

Test Coverage

• Unit tests added/updated
• Integration tests added/updated
• All tests pass locally (make test or uv run pytest)
• Test coverage maintained or improved

Manual Testing

Test steps:

1. Ran uv run python -m pare.main scenarios --help to verify the new CLI registration and command surface.
2. Ran uv run pytest tests/cli/test_scenarios_cli.py to verify the new CLI behavior.
3. Ran make check and uv run deptry pare to verify linting, typing, and dependency checks.

Test environment:

• OS: macOS
• Python version: 3.12.11
• Relevant models used (if applicable): None

Code Quality

• Pre-commit hooks pass (see output below)
• No dependency issues (uv run deptry pare)
• Code follows project style guidelines (f-strings, Google docstrings, etc.)

Pre-commit output:

uv run deptry pare
Success! No dependency issues found.

[deepakn97]

Why do we need this change?
Why is the language marked as system?

[JasonZ-c]

it's because our project depends on a specific Python version and a uv-managed environment
pre-commit’s default isolated env was not reliably reproducing that and may cause error during the pre-commit check

[JasonZ-c]

so in this case the language: system tells pre-commit not to build a separate env while
uv run mypy ensures the hook runs in the same environment the project actually uses

[deepakn97]

The solution is actually simpler. You just need to run uv run git commit -m "<message>".

[JasonZ-c]

nice it's working, a quick note that should we add this cmd to Readme.md?

[JasonZ-c]

no worries, actually I just added it here in previous commit

[deepakn97]

Why are scripts first party? Scripts is not a package and deptry should not run on them?

[JasonZ-c]

it's due to in the orchestrator code we imported the run_scenarios file in scripts folder here, should we move run_scenarios under pare/ instead? so that we can remove "scripts" from known_first_party.