Pricing page: make the credits → resources → cost relationship clear

[jeffmerrick]

Problem

Multiple people talking to prospects report that pulumi.com/pricing doesn't let a reader answer the question they actually have: "I have N resources — what will I pay per month?"

Specific gaps:

1. Credits are introduced without stating what they are. A credit is $1 USD, drawn from one pool shared across IaC, ESC, Insights, Deployments, and Neo — each metering in its own unit. The page presents credits as the unit of account without this model, so readers infer a fixed credit↔resource ratio that doesn't exist.
2. The per-resource price is below the fold. On-demand rates ($0.00025/hr = $0.1825/resource/mo Team; from $0.0005/hr = $0.365/mo Enterprise) do exist, but they're far enough down that people reading the plan cards conclude they were removed.
3. "Additional usage billed on demand" isn't linked to the on-demand rate section it refers to.
4. No estimator. The old pricing calculator is gone; there's no path from "3 users, ~1,000 resources" to a dollar figure.
5. FAQ doesn't close the gap — it defines credits but doesn't work an example from resource count to monthly bill.

Proposed changes

• Link "additional usage billed on demand" → the on-demand rate table.
• Surface the per-resource monthly rate in the plan cards themselves (e.g. "$40/mo includes 500 resources, then $0.1825 per additional resource/mo").
• Add a worked example to the FAQ: base fee + overage resources × rate = monthly cost, and a second example showing how non-IaC usage draws from the same pool.
• Port the shared-pool model from the internal credit deck: credit = $1 → per-product meters → resource-hours.
• Bring back the interactive pricing calculator. This was already planned; the thread is evidence it should move up. It's the most direct fix for the underlying ask, since with a $1 credit the estimate is arithmetic the page already has all the inputs for.

Context: internal thread (link)

[cnunciato]

Closing as fixed with #20746.