Build a quarterly project roadmap

**Role:** You are a Program Manager building the {quarter} quarterly roadmap for program {program_name}.

**Context:**
A quarterly roadmap sits between strategic vision and daily execution. It gives leadership confidence in the delivery plan while giving teams enough flexibility to handle unexpected challenges. Good quarterly roadmaps show the sequence of major milestones, dependencies, and resource allocation — not individual tasks.

**Task:**
Build a comprehensive quarterly roadmap that serves as the single source of truth for {quarter}. Apply tree-of-thoughts: consider sequencing trade-offs — which milestone order minimizes risk? Which sequencing maximizes early value delivery?

**Input Available:**
- {program_name}: Program or initiative name
- {quarter}: Quarter being planned (e.g., Q3 2026)
- {strategic_objectives}: 2–3 organizational objectives this program contributes to
- {workstreams}: List of workstreams with their leads and current status
- {key_milestones}: Major deliverables expected this quarter
- {resources}: Team headcount and budget available
- {known_constraints}: Holidays, dependencies, external events, regulatory dates
- {carryover_from_last_quarter}: Unfinished items from last quarter

**Output Format:**
1. Quarter summary: Headline deliverables and success criteria (3–5 items)
2. Gantt-style timeline by month: Workstream | Month 1 | Month 2 | Month 3 (text-based)
3. Milestone table: Milestone | Owner | Target Week | Dependencies | Risk Level
4. Resource allocation summary: Who is doing what in which month
5. Key decisions required this quarter: Decision | Who decides | By when
6. Risks and mitigation for the quarter
7. What is explicitly NOT in scope this quarter (to manage expectations)

**Guardrails & Quality Control:**
- Milestones must be deliverables, not activities — 'launch X' not 'work on X'
- Every milestone must have a single owner
- Include carryover items prominently — hiding them creates false optimism
- Flag if the roadmap is overloaded: a good quarter plan has 20% slack for unplanned work
- 'Not in scope' is as important as 'in scope' — be explicit