Add end-to-end Cram Mode intake → mocked plan flow in renderer UI

[Copilot]

This PR implements the first full Cram Mode product slice in the real app UI using mocked structured output. Users can now enter exam context from Home/session UI and land on a real results screen with the intended study-plan structure.

• Entry point + screen routing

  • Added a visible Cram Mode action in the top bar.
  • Introduced explicit view switching between:
    • Home/session chat view
    • Cram intake view
    • Cram results view

• Cram intake experience

  • Added a real intake form with required fields:
    • Exam name
    • Time left
    • Exam material
  • Added optional notes input.
  • Added a single primary submit action and back navigation.
  • Added intake empty-state messaging for missing required inputs.

• Mocked results rendering

  • Added mocked plan generation from intake payload and rendered structured sections:
    • Study First
    • Study Next
    • Skip If Needed
    • Likely Questions
    • Quick Self-Test
    • Tonight’s Plan
  • Added results empty-state handling when no sections are present.
  • Added Start Over path to return to intake and re-run flow.

• Loading-state behavior

  • Added explicit submit/loading state during plan generation.
  • Disabled intake actions while loading.
  • Replaced inline magic numbers with named constants for loading delay and material preview window.

• Focused test coverage

  • Extended renderer jsdom test harness to include Cram Mode DOM nodes.
  • Added intake→submit→results test asserting all required section headers and title rendering.

const plan = createCramMockPlan({ examName, timeLeft, material, notes });
renderCramResults(plan); // renders all six required sections