Implement optimistic UI updates for payment submissions

[Kingsman-99]

Overview

After submitting a payment the UI waits for on-chain confirmation before updating. Add optimistic updates so the progress bar and funded amount reflect the payment immediately while confirmation is pending.

Acceptance Criteria

• On payment submit, immediately update the invoice's funded_amount in the React Query cache
• Progress bar animates to the new value within 200 ms of form submission
• "Pending" badge shown on the invoice card while confirmation is in-flight
• On confirmation success: badge removed, cache refreshed with on-chain data
• On confirmation failure: roll back the optimistic update; show error toast with "Try Again"
• Optimistic update keyed by transaction hash — multiple in-flight payments handled independently
• Works for both regular pay_invoice and delegated payments
• Unit tests: mock confirmation success path, mock confirmation failure rollback

[BigMick03]

@BigMick03 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Good morning boss, I will like to do this.

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[aliyuHabibu]

@aliyuHabibu has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi please assign this issue to me. Thank you

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[Stanley-Owoh]

@Stanley-Owoh has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Good day maintainer please i would like to work on this issue please assign it to me i can get it done immediately with positive results thank you

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[egwujiohaifesinachiperpetual-max]

@egwujiohaifesinachiperpetual-max has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi, I'd like to work on this issue! because I am very conversant with solving problems like this, and i can submit the pr with 48hr

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[topboy192]

@topboy192 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

i will like to do this

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[uzochukwuV]

@uzochukwuV has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello, I’m a developer and I’ve accessed this issue. I strongly believe I can solve it. Please assign it to me

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[khanavi272-spec]

@khanavi272-spec has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this issue

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[Levi-Ojukwu]

@Levi-Ojukwu has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello maintainer, I can handle this issue.

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[Bojest001]

@Bojest001 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi maintainer I will to work on this issue

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[khaylebfortune]

@khaylebfortune has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello Maintainer, I can fix this issue.

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[samueloyibodevv]

@samueloyibodevv has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello @maintainer, I’d like to work on this issue. I have experience handling similar tasks and can start immediately. And I will deliver at the shortest possible time.

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