[BUG] Invalidate per-view state after reset and settings import

[easonLiangWorldedtech]

Problem

When a user performs a full reset or imports settings in parallel mode, the per-view state is not invalidated across all running webview instances. This causes:

1. Stale mode and currentApiConfigName persist in view-local state after reset
2. Settings import does not broadcast invalidation to parallel tabs
3. Parallel tabs continue operating with outdated configuration selections

Solution

Hook into the existing broadcast mechanisms to clear per-view state:

• Reset: broadcastResetToAllInstances now clears both in-memory and durable view state for all instances
• Settings import: Added broadcast hook + try/catch wrapper around reset broadcast after settings import completes
• Each instance receives the invalidation signal and reloads its merged state from global defaults

Scope

• broadcastResetToAllInstances: clear local + durable view state on reset
• Settings import: wrap reset broadcast in try/catch, ensure all parallel tabs receive invalidation
• Depends on PR fix(webview): add durable per-view state base #977 (feat/view-local-state-base) for the per-view state foundation

Tests

• Targeted reset/import tests: 81 passed

Related

• Old Issue [BUG] Multi-tab mode/model settings get overwritten by latest task #908 (historical context)
• Old PR fix(webview): isolate parallel provider view state #909 (parent PR)