Initial commit: BMAD framework + Story 1.1 Component Trait Definition

Features:
- BMAD (Build Modular AI-driven Development) framework setup
- BMM, BMB, CIS, Core modules configured
- Story 1.1: Component trait with error handling
- Workspace Cargo.toml with components crate
- 31 tests passing (19 unit + 12 doc tests)

Technical:
- Component trait with compute_residuals, jacobian_entries, n_equations
- ComponentError enum with thiserror
- JacobianBuilder for sparse matrix construction
- Object-safe trait supporting Box<dyn Component>
- Comprehensive documentation and examples

_bmad/bmm/workflows/4-implementation/create-story/template.md

@@ -0,0 +1,49 @@
+# Story {{epic_num}}.{{story_num}}: {{story_title}}
+
+Status: ready-for-dev
+
+<!-- Note: Validation is optional. Run validate-create-story for quality check before dev-story. -->
+
+## Story
+
+As a {{role}},
+I want {{action}},
+so that {{benefit}}.
+
+## Acceptance Criteria
+
+1. [Add acceptance criteria from epics/PRD]
+
+## Tasks / Subtasks
+
+- [ ] Task 1 (AC: #)
+  - [ ] Subtask 1.1
+- [ ] Task 2 (AC: #)
+  - [ ] Subtask 2.1
+
+## Dev Notes
+
+- Relevant architecture patterns and constraints
+- Source tree components to touch
+- Testing standards summary
+
+### Project Structure Notes
+
+- Alignment with unified project structure (paths, modules, naming)
+- Detected conflicts or variances (with rationale)
+
+### References
+
+- Cite all technical details with source paths and sections, e.g. [Source: docs/<file>.md#Section]
+
+## Dev Agent Record
+
+### Agent Model Used
+
+{{agent_model_name_version}}
+
+### Debug Log References
+
+### Completion Notes List
+
+### File List