[codex] implement epic 11 lesson flow

[PilHliP211]

What changed

• added the Epic 11 lesson flow, including lesson state, provider/context wiring, runner utilities, XP helpers, and the lesson play area
• loaded lesson JSON content packs and added the first Japan lesson under content/flag-hunter/lessons/001-japan/lesson.json
• wired map node selection into the new lesson screen and updated tests and fixtures around content loading and progression
• removed the old dev harness screens and content that were replaced by the lesson flow
• fixed the Phase 1 Blockly experience so the first toolbox category opens immediately and the workspace has a real height for rendering and drag/drop

Why it changed

Epic 11 needed a human-testable lesson experience instead of isolated harnesses. During validation, Phase 1 also showed a Blockly regression: the workspace container only had min-height, so Blockly's injected surface could not size itself correctly, and the initial toolbox category was not opened, which made drag-and-drop appear broken and hid the Move East block from learners.

Impact

• learners can launch into the Japan lesson from the map and progress through the three lesson phases
• Phase 1 now visibly exposes the movement blocks and supports drag/drop as expected
• the content system now understands lesson packs alongside the course pack

Validation

• npm run lint
• npx tsc --noEmit
• npm run test
• npm run format:check
• npm run build
• local Playwright human-flow validation of the Japan lesson: enter name, start quest, open Japan, drag Move East, run, confirm progression