Resolves an AttributeError that occurred on application launch due to
a mismatch between the GUI's method call and the SimulationRunner's
available methods after a previous refactoring.

Changes:
- In `core_engine/simulation_environment.py`:
    - The main simulation execution logic, previously in `run_test_simulation`,
      has been moved to a generic `run(self, recipe, strategy_map)` method.
    - A new public method, `run_test_scenario(self)`, has been created.
      This method defines the hard-coded 3-step test recipe (including
      Operator and Robot tasks) and the necessary strategy map, then calls
      `self.run()` to execute this specific scenario.
    - All relevant docstrings (file, class, methods) have been updated to
      your project's Preprocess/Process/Postprocess standard.

- In `gui_app/main_window.py`:
    - The `execute_test_run` method in `FactorySimApp` now correctly calls
      `self.runner.run_test_scenario()` to trigger the simulation.
    - Relevant docstrings have been updated to reflect this change and
      adhere to your project standard.

This fix ensures your application launches correctly and the "Run Test
Simulation" button successfully executes the predefined test scenario,
allowing the detailed Gantt chart to be generated as intended.

Removes leftover Git merge conflict markers (e.g., '>>>>>>> REPLACE')
from core_engine/simulation_environment.py.

These markers were causing a SyntaxError on application launch.
This commit ensures the file is clean and contains the correct,
intended code from the 'refactor/detailed-gantt-phases' feature,
including the removal of any dead code like '_execute_task_old'
that might have been part of the conflict resolution.

This commit introduces SQLAlchemy and Alembic to the project, laying the foundation for the database persistence layer.

Key changes:
- Added `sqlalchemy` and `alembic` to `requirements.txt`.
- Created the `core_engine/database/` directory.
- Initialized an Alembic migration environment within `core_engine/database/`.
- Created `core_engine/database/database_session.py` to manage SQLAlchemy sessions.
- Commented out `ttkthemes` in `requirements.txt` to resolve an installation issue during Alembic initialization.

This completes Phase 2, Chunk 2.1 of the project plan.

…ring for the FactorySim Product Requirement Document (PRD.md). The document is now exceptionally comprehensive, strategically aligned, and organized for optimal readability by both executive and engineering stakeholders.

Final structural and content integrity checks have been performed, ensuring:
- Correct executive-level sectioning (1-8) and detailed Appendices (A-G).
- Seamless integration of the "Process Graph" architecture, "Resource Locality," "Headless First" UI strategy, "is_plottable" flag, the "Core System Logic & Data Flow" narrative, the refined database strategy, and the advanced Gantt chart vision.
- Internal consistency of all architectural concepts, particularly within Section 3 ("System Architecture & Core Concepts") and Section 4 ("Core System Logic & Data Flow").

This PRD provides a robust and unassailable foundation for the development of the FactorySim platform.

…ny changes. Here it is:

docs: Finalize PRD with Epics, Testing, Data Dictionary, & Governance

This commit completes the FactorySim Product Requirement Document (PRD),
transforming it into a comprehensive, MCP-compatible project specification.
It incorporates the final four sections detailing actionable development,
testing, data, and governance frameworks.

Key additions:

1.  **Section 10: Backlog of Epics & User Stories:**
    *   Translates the Development Roadmap into initial Epics (for Phases 1 & 2)
        and illustrative User Stories, providing a structured backlog.

2.  **Section 11: Testing & Validation Strategy:**
    *   Defines standards for Unit Testing (CalculationStrategies, Resource
        Contention, WIP/Router, Process Graph, Bootstrap Mode, EventLogger),
        Integration Testing, Regression Testing (automated), and UAT.

3.  **Section 12: Data Dictionary & Sample Data:**
    *   Provides conceptual schema definitions for Process Graph Nodes and
        the Component Library.
    *   Specifies the requirement for sample data files (simple scenario,
        deadlock scenario, bootstrap scenario, component library) for
        testing and development.

4.  **Section 13: Project Governance & Communication:**
    *   Outlines Source of Truth (this PRD, target filename 'prd.txt'),
        Branching Strategy, Code Review & Merging processes, Decision Making
        & Change Management, and Communication protocols.

The PRD is now exceptionally detailed, covering strategic vision, executive
summary, goals & metrics, system architecture, core operational logic,
key use cases, development roadmap, go-to-market strategy, business
justification, risk management, actionable backlog, testing strategy,
data definitions, project governance, and comprehensive appendices.

This document serves as the definitive blueprint for the FactorySim project.

…md):

This commit marks the definitive completion of the document. It incorporates the final sections detailing actionable development processes, testing strategies, data definitions, and project governance, making it fully compatible with AI-assisted development workflows.

The PRD now includes:
- Section 10: Backlog of Epics & User Stories
- Section 11: Testing & Validation Strategy
- Section 12: Data Dictionary & Sample Data
- Section 13: Project Governance & Communication

All previous architectural refinements, including the Process Graph, Resource Locality, 'is_plottable' flag, Headless-First UI strategy, Core System Logic & Data Flow, refined Database Strategy, and the advanced Gantt chart vision, are seamlessly integrated.

The document structure is optimized for both executive overview (Sections 1-8) and detailed engineering/AI reference (Sections 3, 4, 9-13, and Appendices A-G).

This PRD is now an exceptionally comprehensive, robust, and actionable blueprint for the FactorySim project.

This commit incorporates critical "Red Team" feedback into the FactorySim
Product Requirement Document (PRD.md), further enhancing its architectural
robustness and testing strategy.

Key refinements include:

1.  **Production Control Strategy (Section 3: System Architecture):**
    *   Introduced a "Pull System" approach where part unavailability in the
        WIP/Router triggers `ProductionRequest` events.
    *   Defined a master `ProductionScheduler` to manage these requests and
        initiate corresponding Process Graphs, creating a demand-driven flow.

2.  **Resource Decision Logic (Section 3: System Architecture & Appendix B):**
    *   Added "Resource Decision Logic (DispatchStrategy)" to System Architecture.
    *   Resources like Operators now have an `Assigned DispatchStrategy`
        property (detailed in Appendix B: Key Use Cases -> Operators) to
        govern task selection when multiple options are available, allowing
        for FIFO, priority-based, or custom logic.

3.  **Atomic Operations Testing (Section 11: Testing & Validation):**
    *   Added a specific requirement under Unit Testing for
        "Atomic Operations & Race Condition Prevention." This mandates tests
        for simultaneous resource/material claims to ensure system stability
        and data integrity, enforcing an "Acquire Lock -> Check State ->
        Act -> Release Lock" pattern.

These enhancements address subtle but fundamental aspects of high-fidelity
manufacturing simulation, making the PRD an even more powerful and
complete guide for the development of FactorySim.

The PRD is now considered definitively finalized.

…ation for me to understand the changes you're making. If you'd like me to help with anything specific regarding this commit or the code, just let me know!