Preserve app ownership across WireGuard policy reloads

[kasnder]

WireGuard policy reloads recheck the owner of established TCP connections. Android can return UID 0 for a closing connection that previously belonged to an ordinary app, causing its tracker activity to appear as “Unidentified app (UID 0)”. Device logs confirmed the same connection changing from Play Store UID 10276 to UID 0 after a reload.

Retain numeric TCP ownership in a bounded cache independent of route and blocking-policy generations. Refreshes still apply current routing and blocking decisions; fresh SYNs discard the previous owner. Uncached established connections with ambiguous UID 0 remain unresolved and fail closed. Atomic cache invalidation avoids a lifecycle race, and cached packets retain the existing route fast path.

Validation:

• Production-bound packet-policy and owner-cache tests pass with ASan/UBSan on the host, covering IPv4/IPv6, root UID, tuple reuse, expiry, collisions and route-call counts.
• Regression checks fail when the original attribution bug or reviewed cache/fast-path bugs are restored.
• Android native regression binaries compile with UBSan; assembleGithubDebug passes with all four native ABIs packaged.
• Independent Sol review completed; lifecycle and performance findings were corrected and rechecked.

Final device execution and installation remain unverified because the Pixel disconnected. Existing timeline records are not rewritten.