docs: add implementation plan, ADRs, and task tracking system

- Add comprehensive 8-phase implementation plan (docs/plan.md)
- Add 28 Architecture Decision Records (docs/adr/) covering all phases
- Add task tracking system with 283+ task files (docs/stories/)
- Add task generator script for automated task file creation
- Add reference playbooks and requirements documentation

This commit establishes the complete planning foundation for the Go
Platform implementation, documenting all architectural decisions and
providing detailed task breakdown for Phases 0-8.

docs/adr/0003-dependency-injection-framework.md

@@ -0,0 +1,49 @@
+# ADR-0003: Dependency Injection Framework
+
+## Status
+Accepted
+
+## Context
+The platform requires dependency injection to:
+- Manage service lifecycle
+- Wire dependencies between components
+- Support module system initialization
+- Handle graceful shutdown
+- Provide testability through dependency substitution
+
+Options considered:
+1. **uber-go/fx** - Runtime dependency injection with lifecycle management
+2. **uber-go/dig** - Compile-time dependency injection
+3. **Manual constructor injection** - No framework, explicit wiring
+
+## Decision
+Use **uber-go/fx** (v1.23.0+) as the dependency injection framework.
+
+**Rationale:**
+- Provides lifecycle management (OnStart/OnStop hooks) crucial for services
+- Supports module-based architecture through fx.Option composition
+- Runtime dependency resolution with compile-time type safety
+- Excellent for modular monolith architecture
+- Well-documented and actively maintained
+- Used by major Go projects (Uber, etc.)
+
+## Consequences
+
+### Positive
+- Clean lifecycle management for services
+- Easy module composition via fx.Option
+- Graceful shutdown handling built-in
+- Test-friendly with fx.Options for test overrides
+
+### Negative
+- Runtime reflection overhead (minimal)
+- Learning curve for developers unfamiliar with fx
+- Slightly more complex error messages on dependency resolution failures
+
+### Implementation Notes
+- Install: `go get go.uber.org/fx@v1.23.0`
+- Create `internal/di/container.go` with fx.New()
+- Use fx.Provide() for service registration
+- Use fx.Invoke() for initialization tasks
+- Leverage fx.Lifecycle for service startup/shutdown
+