feat(cmo): guided wizard — one action at a time

Why

Turn the project dashboard from a static list of cards into a step-by-step launch guide. Asked-for behaviour: open project → present one task → generate content → validate → next.

What

• GET /api/projects/<id>/wizard/next returns the next pending action (highest priority) with progress counter, or complete: true when done.
• /projects/<id>/wizard/ serves a new single-card view with custom previews per action kind (HTML iframe for landing_page, capsule grid for capsule_set, fact-sheet/checklist tabs for press_kit, JSON otherwise).
• Buttons: Generate / Regenerate / Approve & next / Skip. Reuses the existing executor + status endpoints — no new generation code, no schema changes.
• "Open guided wizard →" link added to the project detail header.

Verification

• HTML route 200, GET /api/projects/<id>/wizard/next returns the right pending action with progress 4/6 on aziz/cnc.
• Full pytest suite green (352).

Test plan

• Open https://cmo.laparedita.com/projects/53e8d9e7-6438-4f1d-83ab-4ca4863202d8/wizard/
• Verify "screenshot_capture" appears as next pending action (executable=false → only Approve/Skip).
• Mark a few done, confirm progress bar advances and the next card loads.