Refactor task management structure and update documentation

- Changed the directory structure for task specifications to include a dedicated `todo/` folder within `_docs/02_tasks/` for tasks ready for implementation.
- Updated references in various skills and documentation to reflect the new task lifecycle, including changes in the `implementer` and `decompose` skills.
- Enhanced the README and flow documentation to clarify the new task organization and its implications for the implementation process.

These updates improve task management clarity and streamline the implementation workflow.

_docs/02_tasks/done/AZ-143_test_video.md

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+# Video Processing Tests
+
+**Task**: AZ-143_test_video
+**Name**: Video Processing Tests
+**Description**: Implement E2E tests verifying video frame sampling, annotation interval enforcement, and movement-based tracking
+**Complexity**: 3 points
+**Dependencies**: AZ-138_test_infrastructure, AZ-142_test_async_sse
+**Component**: Integration Tests
+**Jira**: AZ-143
+**Epic**: AZ-137
+
+## Problem
+
+Video detection processes frames at a configurable interval (frame_period_recognition), enforces minimum annotation intervals (frame_recognition_seconds), and tracks object movement to avoid redundant annotations. Tests must verify these three video-specific behaviors work correctly.
+
+## Outcome
+
+- Frame sampling verified: only every Nth frame processed (±10% tolerance)
+- Annotation interval enforced: no two annotations closer than configured seconds
+- Movement tracking confirmed: annotations emitted on object movement, suppressed for static objects
+
+## Scope
+
+### Included
+- FT-P-10: Video frame sampling processes every Nth frame
+- FT-P-11: Video annotation interval enforcement
+- FT-P-12: Video tracking accepts new annotations on movement
+
+### Excluded
+- Async detection initiation (covered in async/SSE tests)
+- SSE delivery mechanics (covered in async/SSE tests)
+- Video processing performance (covered in performance tests)
+
+## Acceptance Criteria
+
+**AC-1: Frame sampling**
+Given a 10s 30fps video (300 frames) and frame_period_recognition=4
+When async detection is triggered
+Then approximately 75 frames are processed (±10% tolerance)
+
+**AC-2: Annotation interval**
+Given a test video and frame_recognition_seconds=2
+When async detection is triggered
+Then minimum gap between consecutive annotation events >= 2 seconds
+
+**AC-3: Movement tracking**
+Given a test video with moving objects and tracking_distance_confidence > 0
+When async detection is triggered
+Then annotations contain updated positions for moving objects
+And static objects do not generate redundant annotations
+
+## Non-Functional Requirements
+
+**Performance**
+- Video processing completes within 120s
+
+## Integration Tests
+
+| AC Ref | Initial Data/Conditions | What to Test | Expected Behavior | NFR References |
+|--------|------------------------|-------------|-------------------|----------------|
+| AC-1 | Engine warm, SSE connected, test-video, frame_period=4 | Count processed frames via SSE | ~75 frames (±10%) | Max 120s |
+| AC-2 | Engine warm, SSE connected, test-video, frame_recognition_seconds=2 | Measure time between annotations | >= 2s gap between annotations | Max 120s |
+| AC-3 | Engine warm, SSE connected, test-video, tracking config | Inspect annotation positions | Updated coords for moving objects | Max 120s |
+
+## Constraints
+
+- Test video must contain moving objects for tracking verification
+- Frame counting tolerance accounts for start/end frame edge cases
+- Annotation interval measurement requires clock precision within 0.5s
+
+## Risks & Mitigation
+
+**Risk 1: Inconsistent frame counts**
+- *Risk*: Frame sampling may vary slightly depending on video codec and frame extraction
+- *Mitigation*: Use ±10% tolerance as specified in test spec