Add CHANGELOG.md for v0.4.0 release

Author: francois-drielsma

CHANGELOG.md

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+# Changelog
+
+All notable changes to the SPINE Production System will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [0.4.0] - 2026-02-10
+
+**Post-reformatting baseline release** - Major architectural overhaul of the configuration system and codebase structure. This release marks a stable reference point before planned architectural evolution.
+
+### ⚠️ Breaking Changes
+- **Requires SPINE v0.9.0 or later**
+- Configuration directory structure completely reorganized
+- Include paths in existing configurations need updating
+
+### What's Changed
+
+- **Complete Configuration System Restructure:**
+  - Introduced modular organization with separation of concerns
+  - Mode-agnostic model configurations now in `config/common/model/`
+  - Mode-specific configs (base/io/post) organized under `config/{infer,train}/{detector}/`
+  - Implemented intelligent fallback resolution: detector-specific → common defaults
+  - New standardized naming conventions with date-stamped configuration files
+  
+- **Submitter Codebase Modularization:**
+  - Refactored monolithic submission script into maintainable modules
+  - Separated concerns: configuration management, file handling, SLURM client
+  - Improved code structure for extensibility and testing
+  
+- **Enhanced Job Submission Features:**
+  - Local directory mode: jobs write to `--local-dir` by default (use `--central-dir` for production)
+  - Better dependency handling for multi-array job requirements
+  - Improved chunking logic with sequential execution guarantees
+  - Smart job array generation (skips arrays for single-task jobs)
+  
+- **Extended Detector Support:**
+  - Added DUNE 10kt-1x2x6 inference configurations
+  - Improved NERSC cluster integration
+
+### Migration Guide
+
+For users with custom v0.3.x configurations, see detailed migration instructions in `config/common/README.md` and `config/infer/README.md`. Key steps:
+
+1. Reorganize model configs → `config/common/model/`
+2. Move detector-specific inference configs → `config/infer/{detector}/`
+3. Update include paths in composite configurations
+4. Update SPINE dependency to v0.9.0+
+
+Full Changelog: [v0.3.1...v0.4.0](https://github.com/DeepLearnPhysics/spine-prod/compare/v0.3.1...v0.4.0)
+
+---
+
+## [0.3.1] - 2025-12-19
+Fixed issue with `shower_start_merge` blocks in ICARUS configurations.
+
+See [GitHub release](https://github.com/DeepLearnPhysics/spine-prod/releases/tag/v0.3.1) for details.
+
+## [0.3.0] - 2025-12-17
+Updated all configurations to reflect SPINE v0.8.0 geometry handling changes. Created new `geo` blocks, renamed `ndlar` to `nd-lar`, restructured detector naming conventions.
+
+See [GitHub release](https://github.com/DeepLearnPhysics/spine-prod/releases/tag/v0.3.0) for details.
+
+## [0.2.5] - 2025-12-12
+Last release before geometry handling overhaul. Added lithification configurations, latest ICARUS production configs (250625), new ND-LAr configurations, and single 2x2 module support.
+
+See [GitHub release](https://github.com/DeepLearnPhysics/spine-prod/releases/tag/v0.2.5) for details.
+
+## [0.2.4] - 2025-09-04
+Updated SBND configurations: interaction clustering anchored to tracks, backtracking fixes, containment module updates, MCS resolution modeling improvements.
+
+See [GitHub release](https://github.com/DeepLearnPhysics/spine-prod/releases/tag/v0.2.4) for details.
+
+## [0.2.3] - 2025-08-18
+Updated SBND configurations: containment checks, cathode crosser handling, flash matching improvements.
+
+See [GitHub release](https://github.com/DeepLearnPhysics/spine-prod/releases/tag/v0.2.3) for details.
+
+## [0.2.2] - 2025-07-30
+Bug fixes, shower quality attributes, SBND calibration updates, CRT info integration, cathode crosser post-processor.
+
+See [GitHub release](https://github.com/DeepLearnPhysics/spine-prod/releases/tag/v0.2.2) for details.
+
+## [0.2.1] - 2025-03-31
+Additional configurations for ICARUS and SBND. Compatible with SPINE v0.2.0 through v0.3.X.
+
+See [GitHub release](https://github.com/DeepLearnPhysics/spine-prod/releases/tag/v0.2.1) for details.
+
+## [0.2.0] - 2025-01-17
+All configurations work with SPINE v0.2.X. Flash matching configurations incompatible with SPINE v0.1.3 and below.
+
+See [GitHub release](https://github.com/DeepLearnPhysics/spine-prod/releases/tag/v0.2.0) for details.
+
+## [0.1.0] - 2024-11-25
+First reference release. All configurations work with SPINE v0.1.X. Flash matching configurations incompatible with SPINE v0.2.0 and above.
+
+See [GitHub release](https://github.com/DeepLearnPhysics/spine-prod/releases/tag/v0.1.0) for details.