feat: ship v2 organizer rewrite

[PBandDev]

This PR ships the full v2 organizer rewrite. The extension now uses a pure-function layout framework centered on a Sugiyama-style flow algorithm instead of the older ad hoc pipeline, with hardened runtime modeling for ComfyUI graphs, groups, nested groups, selected-group organize behavior, subgraph input/output nodes, and token-aware layout. It also adds the user-facing follow-up work from the v2 line, including the QoL settings panel, configurable spacing, context-aware Shift+O, fit-to-view behavior, and the runtime/layout fixes needed to make those behaviors reliable in real ComfyUI sessions.

The testing and release story is also substantially upgraded. The branch adds broad unit coverage for the framework and adapter layer, property-based invariant tests, Playwright E2E coverage against a pinned ComfyUI checkout, visual-regression coverage for real workflows, and CI/publish workflow updates so that E2E coverage runs in automation. The latest follow-up change removes the large git-tracked captured upstream workflow corpus and replaces it with runtime discovery of installed templates from the pinned comfyui-workflow-templates package via the Python API, deriving the exact package version from the pinned ComfyUI checkout's requirements.txt so the broad upstream workflow suite stays deterministic without freezing hundreds of JSON fixtures in this repo.

Verification used on the equivalent v2 tree before opening this PR: pnpm typecheck, pnpm test, pnpm build, pnpm setup:e2e, and pnpm test:e2e.