Focus Session Planner

**Context**: As a productivity tool, a Focus Session Planner is designed to help individuals prioritize tasks, manage time, and maintain concentration on critical activities. The goal is to create a schedule that optimizes work sessions, allowing users to make the most of their time and energy.

**Detailed Instructions**: 
Design a Focus Session Planner that takes into account the user's tasks, priorities, and time constraints. The planner should be able to:
1. Accept a list of tasks with their respective durations and priority levels.
2. Allocate these tasks into focused work sessions, each lasting between 25 minutes to 120 minutes, with breaks in between.
3. Consider the user's most productive hours of the day and schedule critical tasks accordingly.
4. Allow for customization of the planner based on the user's work style, including the ability to set specific work hours, breaks, and session lengths.
5. Provide an option to integrate with calendar systems to avoid scheduling conflicts.
6. Offer suggestions for improving productivity, such as minimizing distractions during focus sessions and utilizing breaks effectively.

**Output Format**: The output should be a structured schedule for the day, including:
- Start and end times for each focus session
- Task(s) to be completed during each session
- Break times and their durations
- Recommendations for staying focused and managing distractions
- Optional: Integration with the user's calendar to block out scheduled focus sessions and breaks

**Examples**:
- Input: A list of 5 tasks with priorities (High, Medium, Low) and estimated durations (30 minutes, 60 minutes, 90 minutes, 30 minutes, 60 minutes).
- Output: A suggested schedule for an 8-hour workday, with 4 focus sessions, each followed by a 10-15 minute break, and a 30-minute lunch break. The schedule should prioritize high and medium tasks during the user's most productive hours.