test: cover wallet-balance and E.164 money paths

[rajarshidattapy]

What

Fixes #1

First tests for the money-adjacent paths in cli/ / tui/, which had zero coverage. A silent regression here costs real money (wrong wallet display before a billable call, or a malformed number dialed).

Path	Test file	Pins
UserInfo.Balance()	internal/api/account_test.go	/100 wallet scaling (the 22bc0ef bug), zero balance, wallet precedence over fallback fields, unscaled fallbacks, missing/wrong-type field, and the $%.2f confirmation-summary format
e164Pattern	internal/tui/callstart_test.go	recipient-number accept/reject boundary (min/max length, leading zero, spaces/dashes/parens, missing +) that gates a real outbound call

Stdlib testing only, table-driven to match the existing client_test.go. Both paths are pure functions — no network, no RPC mock needed. go test ./... passes.

Scope note

The issue's wording ("transfer amounts", "addresses", "RPC") is boilerplate from a different project. This repo is a Go voice-agent CLI with no fund transfers, RPC, or crypto addresses, so I mapped the intent onto its real money paths: wallet-balance display and the E.164 phone gate before a paid call. There is no amount-input path to test.

Not included (as scoped)

• TUI render/snapshot tests
• Full command-surface coverage

Add once the money paths are locked down.

[rajarshidattapy]

hey @tanisha-byte , whenever you are free, can you look through the 4 PRs, I've put?