bug: meal planning stalls

[NickMonrad]

You: plan meals
Jandal: I need a few details before I build the plan:

• How many people are you cooking for?
• How many days do you want to plan for?
• Any dietary requirements, allergens, or ingredients to avoid?
• What protein preferences should I use?
• Any cuisine or meal-style preferences?

Say 'help' for examples of what you can reply with.
You: 3 people
Jandal: Got it so far: 3 people.

I need a few details before I build the plan:

• How many days do you want to plan for?
• Any dietary requirements, allergens, or ingredients to avoid?
• What protein preferences should I use?
• Any cuisine or meal-style preferences?

Say 'help' for examples of what you can reply with.
You: 5 days
Jandal: Got it so far: 3 people, 5 days.

I need a few details before I build the plan:

• Any dietary requirements, allergens, or ingredients to avoid?
• What protein preferences should I use?
• Any cuisine or meal-style preferences?

Say 'help' for examples of what you can reply with.
You: no dietary requirements
Jandal: Got it so far: 3 people, 5 days, no dietary requirements.

I need a few details before I build the plan:

• What protein preferences should I use?
• Any cuisine or meal-style preferences?

Say 'help' for examples of what you can reply with.
You: beef mince, chicken, beef
Jandal: Got it so far: 3 people, 5 days, no dietary requirements, chicken, beef mince.

I need a few details before I build the plan:

• Any cuisine or meal-style preferences?

Say 'help' for examples of what you can reply with.
You: italian, mexican
Jandal: I still need to rebuild your meal plan draft. Say 'generate recipes' to try again, 'change preferences', 'help' for more options, or 'cancel'.

[lokhor]

Fixed in #1080.

Root cause: markGenerationFailure(sessionId, null, ...) moved the session to PLAN_REVIEW with empty days and cleared pendingGenerationKind. Follow-up turns showed the confusing "I still need to rebuild..." message instead of the plan.

Fix adds:

• Retry loop (2 attempts) for transient model failures (blank output, invalid JSON)
• Terminal failure calls markGenerationFailure() only after all attempts exhausted
• All empty-plan UX surfaces now show actionable recovery copy
• Stale draft preserved across preference-edit failures

All 69 coordinator tests pass.