feat: finish native customization and platform seams

• 8ac650515f feat: add native post-generate hooks glennmichael123 review this step
• e2ecbeab2c feat(ios): configure tab selection appearance glennmichael123 review this step
• ed6fbb33b8 feat(android): configure tab selection appearance glennmichael123 review this step
• 0438102cc0 docs: describe native project customization glennmichael123 review this step
• 71169f9b4c test: cover native post-generate build hooks glennmichael123 review this step
• e7be262a70 fix(ios): ignore stale watch state updates glennmichael123 review this step
• dd55dada4b fix(macos): open file inputs through WKWebView glennmichael123 review this step
• f8e8e2c05b fix(ios): mirror nested tab bar config glennmichael123 review this step
• 00e99d04df fix(ios): retain tab chrome in selection indicator glennmichael123 review this step
• 341823a3f8 fix(ios): let native screens control interface appearance glennmichael123 review this step
• f40f6f4c89 feat(types): expose app appearance controls glennmichael123 review this step
• d831ee6dc4 fix(ios): preserve native screen appearance config glennmichael123 review this step
• 33853c5568 test(ios): advance appearance action ratchet glennmichael123 review this step
• b29e09da83 fix(ios): update SwiftUI appearance at runtime glennmichael123 review this step
• 56dac5b337 test(ios): ratchet appearance actions glennmichael123 review this step
• 45a33630e4 test(ios): preserve nested config conformance glennmichael123 review this step