Bridge and test hosts

[filvecchiato]

Expose funding to hosts; make it testable.

• UniFFI callbacks and admin exports; Swift/Kotlin bindings
• MockPlatform, CLI funding host
• CLI battery with a provider worker that runs a session end to end; in CI

Done when Both mobile hosts call funding; the CLI battery runs a provider worker end to end in CI.
Depends on #1137
Refs Pattern: NativePocketCallbacks

[filvecchiato]

• feat(truapi): funding sessions, host overlay, native bridge and test host #1315 native (UniFFI) bridge: funding overlay, open_funding and funding_session; make e2e-funding-cli, a local funding battery (delivered, released, failed, dismissed, unknown session) against a scripted CLI funding host, no funds or chain
• feat(truapi)!: payments by id and balance through host platforms #1314 top-up, payment and balance callbacks: set_top_up_callbacks, set_payment_callbacks, set_balance_callbacks with their notify calls
• feat(truapi)!: funding provider trait, reports and settlement #1317 the battery runs a provider worker end to end, with scripted top-up and payment engines and a host restart; CI runs it on every core, CLI or client change