Bone Flow Editor v1.0.39 Candidate

Incident
- VS Code Simple Browser showed "通知により一時停止しました" and Realtime Preview #001 became unusable after extension installation/restart.

Fix scope
- Removed simpleBrowser.show from Bone Flow Editor preview launch paths.
- Bone Flow Editor Preview, Realtime Preview #001, and Markdown Preview #002 now open in a Bone Flow-owned VS Code WebviewPanel.
- The existing extension-owned ephemeral 127.0.0.1 preview server is retained; it remains local-only and uses a dynamic port.
- Webview embeds only that exact local origin/port through frame-src CSP.
- Activation closes stale Bone Flow Simple Browser tabs so the old paused tab does not remain as the apparent active preview.
- #001/#002 bundled runtime and v1.0.38 Markdown handshake files are otherwise preserved.

Verification boundary
- Package/static/mock activation QA can verify command registration, server allocation, served sample bytes, and generated Webview HTML.
- Actual user-side VS Code rendering remains NOT VERIFIED until tested in the user's VS Code.
- Do not mark Completed/Frozen before user confirmation.
