Make scan and customer state consistent across multiple browser tabs

[techmore]

Summary

This issue is still partially relevant, but the problem is narrower now than when it was filed.

What Changed

The codex/runtime-contract-fixes branch already addressed a major part of the multi-tab inconsistency problem:

• per-client runtime state moved onto ClientStateRegistry
• active scan replay for newly connected tabs now lives in a dedicated connection handler
• scan/job/runtime handlers are more consistent about sid-scoped state

Remaining Gap

What likely still remains is hydration and shared-current-view behavior beyond live scan replay:

• how a fresh tab reconstructs the current customer/network/report context when no active replay buffer exists
• which parts of state should be persisted vs remain per-client
• whether current-view hydration should come from persisted state, an API snapshot, or a lightweight shared active-state store

Recommendation

Keep this issue open, but narrow it to the remaining shared-hydration problem rather than the broader per-client state-isolation bug, which is largely addressed by the runtime-state work already landed on the branch.

[techmore]

Tracked as priority 5 in #108. The main state-isolation fixes landed already; the remaining scope is the shared hydration and reconnect consistency gap.

[techmore]

Implemented on codex/runtime-contract-fixes in commit 38a405e.

What landed:

• sid-scoped customer/network/last-target updates now refresh the shared default snapshot for future tabs
• new socket connections hydrate from either the active scan owner state or the shared snapshot
• new tabs now receive customer_info, network_key, client_state_snapshot, and auto_scan_status immediately on connect
• the frontend now uses client_state_snapshot to restore lastScanTarget and seed the target field on reconnect/new-tab open
• regression coverage now verifies active-scan hydration and shared-snapshot hydration paths

Validation:

• ./.venv/bin/python -m pytest -q
• 129 passed

[techmore]

Implemented on and verified in the current test suite. Keeping the detailed implementation notes on the issue comments; closing this as resolved by the branch work.