Add trace path exclude filter

[rogierx]

Addresses part of #41.

This adds an Exclude Paths filter to the trace view. The field accepts comma- or newline-separated path fragments, normalizes them case-insensitively, and filters matching trace nodes and their children out of the displayed tree. That makes common presets such as node_modules or lib.dom.d.ts possible without changing the storage layer or introducing a larger query system.

The filter state is included in the shared filterTree message shape with a default for backwards compatibility.

Validation:

• pnpm exec vitest run test/index.test.ts
• pnpm run typecheck
• pnpm exec eslint src/treeFilters.ts src/traceTree.ts src/handleMessages.ts shared/src/messages.ts ui/app.vue test/index.test.ts
• pnpm exec nuxt build ui
• pnpm exec rollup -c
• git diff --check