frontend: allow entering fiat in lightning receive

[bznein]

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📝 Walkthrough

Walkthrough

The Receive Lightning route component was refactored to improve amount validation and conversion. The component now uses an explicit parseSatsAmount helper and tracks SAT/fiat text as separate state properties instead of relying on effects. Async conversion callbacks replaced effect-based logic, using monotonically increasing request IDs to ignore stale in-flight responses. The form was updated to use NumberInput controls for both fields, with the confirm button's disabled state now derived from satsAmount === undefined. Submission validation uses the pre-computed satsAmount directly and shows translated errors when parsing fails.

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Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@frontends/web/src/routes/lightning/receive/receive.tsx`:
- Around line 236-244: The fiat input uses a SAT-specific translation key
causing incorrect placeholder text: update the NumberInput with id
"amountFiatInput" to use a dedicated fiat/generic key (e.g. replace
t('lightning.receive.amountSats.placeholder') with a new key like
'lightning.receive.amountFiat.placeholder' or
'lightning.receive.amount.placeholder') and add that new key and translations to
the locale files for all supported languages so the NumberInput (component:
NumberInput, prop: placeholder) shows the correct fiat/generic placeholder.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 3e3d0ce1-a432-4ef2-979c-3560bce17ced

📥 Commits

Reviewing files that changed from the base of the PR and between 2536dc6 and 36c61b8.

📒 Files selected for processing (1)

• frontends/web/src/routes/lightning/receive/receive.tsx