fix: normalize invalid saved ids in code and notes

[antonreshetov]

Summary

• normalize stale saved folder, tag, and selected item ids in code and notes spaces
• load folders and tags before list fetch so startup and storage refresh use normalized state
• add regression tests for init and storage-sync paths

Context

• Potentially resolves [Bug]: Code snippets not showing in UI, but total count appears in preferences #729

Test Plan

• pnpm test src/renderer/composables/tests/useCodeSelectionNormalization.test.ts src/renderer/composables/tests/useCodeSpaceInit.test.ts src/renderer/composables/spaces/notes/tests/useNotesSelectionNormalization.test.ts src/renderer/composables/spaces/notes/tests/useNotesSpaceInitialization.test.ts src/renderer/ipc/listeners/tests/system.test.ts
• pnpm exec eslint src/renderer/composables/index.ts src/renderer/composables/useCodeSelectionNormalization.ts src/renderer/composables/useCodeSpaceInit.ts src/renderer/composables/tests/useCodeSelectionNormalization.test.ts src/renderer/composables/tests/useCodeSpaceInit.test.ts src/renderer/composables/spaces/notes/index.ts src/renderer/composables/spaces/notes/useNotesSelectionNormalization.ts src/renderer/composables/spaces/notes/useNotesSpaceInitialization.ts src/renderer/composables/spaces/notes/tests/useNotesSelectionNormalization.test.ts src/renderer/composables/spaces/notes/tests/useNotesSpaceInitialization.test.ts src/renderer/ipc/listeners/system.ts src/renderer/ipc/listeners/tests/system.test.ts