v0.5.1206

cargo-test + iOS simctl gate fixes + runtime/codegen batch

Supersedes the unshipped v0.5.1205 (its simctl gate failed on an iOS build break).

• fix(ui-ios): adbanner.rs used crate::string_header::StringHeader (a module only perry-ui-macos has); now perry_runtime::string::StringHeader like its siblings. Excluded from cargo-test, so only the tag-time simctl build caught it. (#5645)
• fix(stdlib): auto-opt link break — dispatch_http path refs after the dispatch-module split (#1435). (#5639)
• test: blocklist_addsubnet_prefix used TempDir::join (no such method) — broke the full-workspace cargo-test gate (red on nightly since 2026-06-20). Now dir.path().join(...). (#5641)
• fix(net,http,tls): #1781 — SSO short strings in value conversion. (#5638)
• fix(runtime): bind inherited prototype-accessor methods to the receiver. (#5637)
• fix: #5594 — Annex B.3.3.3 global eval function-declaration binding. (#5636)
• fix(temporal): #5580 — era/eraYear for non-ISO calendars. (#5635)
• fix(runtime): #5592 — class X extends <Proxy> segfault. (#5634)
• fix(runtime): #5591 — string-coercing a class/object method no longer segfaults. (#5633)