fix: stabilize swap tab loading states

[huhuanming]

Summary

• keep the Pro token/network badge tree stable and resolve built-in network logos synchronously before using the background fallback
• coordinate cold Stock header, amount input, and positions content until the Stock channel finishes initialization while preserving warm cached content
• render unavailable Pro statistics as -- without collapsing real zero values

Runtime and root cause

This is scoped to iOS Native, where main and bg run in isolated JS heaps and initialize independently.

• Tab switching remounts the active subtree. The token component previously changed from a bare Image branch to an Image plus network-badge container after the async network logo arrived, which remounted the image state.
• Stock identity, market status, pay token, and positions become ready on separate clocks, so their local skeleton conditions exposed multiple replacement phases on a cold entry.
• Pro value renderers treated unavailable values as numeric zero before the real market response arrived.

Verification

• 3 focused Jest suites passed: 35 tests
• yarn agent:check --profile commit passed
• yarn agent:check --profile pr passed
• manually verified first entry and repeated Swap / Stock / Pro switching on iOS Native, including a 10-round audit recording

Scope

• 7 implementation files and 2 focused test files
• no NativeLogger diagnostic instrumentation
• no recordings, slide assets, dependencies, or unrelated worktree changes