feat: add support for route hints from private channels when creating invoices

[pradip-1111]

This PR adds opt-in support for including route hints from private channels when creating invoices.

Motivation:
Users with only private inbound liquidity (e.g. via LSPs) currently experience failed payments when invoices do not include route hints. This improves reliability and UX for such setups.

Changes:

• Added includePrivateChannels flag to MakeInvoiceArgs
• Propagated the flag through background API and message types
• Updated LND and LNC connectors to include private channels when requested
• Added a UI toggle on the Receive Invoice screen

Verification:

• Create an invoice with “Include private channels” enabled
• Decode the invoice and verify route_hints are present when private channels exist

Summary by CodeRabbit

• New Features
  • Added a checkbox on the invoice creation form to let users opt in to include private channels when generating an invoice (off by default). This enables wider routing options for payments when selected.

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[coderabbitai]

📝 Walkthrough

Walkthrough

Adds an optional boolean flag includePrivateChannels to the invoice creation flow and propagates it from the UI form through the client API, background action, connector interfaces, and into LNC/LND invoice creation payloads.

Changes

Cohort / File(s)	Summary
UI Form Layer src/app/screens/ReceiveInvoice/index.tsx	Added includePrivateChannels boolean to form state, updated change handler and defaults, added checkbox UI, and included flag in invoice creation request
Client API & Types src/common/lib/api.ts, src/types.ts	Extended makeInvoice signature and MessageMakeInvoice args to accept includePrivateChannels; passed flag in message request payload
Background Action src/extension/background-script/actions/ln/makeInvoice.ts	Forwarded includePrivateChannels from message args into connector makeInvoice invocation
Connector Interface & Implementations src/extension/background-script/connectors/connector.interface.ts, src/extension/background-script/connectors/lnc.ts, src/extension/background-script/connectors/lnd.ts	Added optional includePrivateChannels to MakeInvoiceArgs; passed as private (LNC/LND) when calling underlying addInvoice endpoints

Sequence Diagram(s)

sequenceDiagram
  participant UI as UI\n(ReceiveInvoice)
  participant API as Client\nAPI (makeInvoice)
  participant BG as Background\nAction (makeInvoice)
  participant Conn as Connector\n(LNC / LND)

  UI->>API: makeInvoice({ amount, memo, includePrivateChannels })
  API->>BG: msg.request("makeInvoice", { amount, memo, includePrivateChannels })
  BG->>Conn: connector.makeInvoice({ amount, memo, includePrivateChannels })
  Conn->>Conn: includePrivateChannels -> map to payload.private
  Conn->>Conn: call addInvoice / POST create invoice
  Conn-->>BG: invoice response
  BG-->>API: response
  API-->>UI: invoice result

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 A little box I gently tick,
From form to API it hops so quick,
Background hums and connectors send,
Private paths now join the send,
An invoice bound, on hops we stick.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main feature being added: support for route hints from private channels when creating invoices, which aligns with the changeset's primary objective.

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✨ Finishing touches

• 📝 Generate docstrings

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@src/app/screens/ReceiveInvoice/index.tsx`:
- Around line 80-87: The state update in setFormData unnecessarily spreads
formData twice; edit the update in ReceiveInvoice's handler so it only spreads
formData once (keep a single ...formData) before applying the dynamic key
[event.target.name] (handling checkbox via (event.target as
HTMLInputElement).checked or event.target.value.trim()) to eliminate the
redundant duplicate spread.

[pradip-1111]

i have updated