EPIC: Planner next action (VS-7)

[kmosoti]

Outcome

The study page recommends exactly one next useful action with a clear reason.

Scope

• NextAction schema
• Weak prerequisite heuristic
• Due review heuristic
• Course outcome fallback
• Skip/stuck tracking
• Planner tests
• Study page integration

Source Docs

• docs/01-requirements.md: Planner
• docs/02-architecture-mermaid.md: Planner Decision Flow

Done When

• Planner chooses weak prerequisite first.
• Planner falls back to due review.
• Planner falls back to next course outcome.
• Every action includes title, reason, and estimated minutes.