v0.9.0: settings dashboard, hardened HTTP service, one look across the web UI

Since v0.8.0: a settings dashboard to see, trace and edit every WayContext setting, write
protection on the local HTTP service, honest boolean parsing, and a shared visual redesign of
the knowledge graph, settings and Decision Review pages. Two breaking changes — read them before
upgrading.

• Redesigned the knowledge graph, settings and Decision Review pages in one shared visual
  style (dark mode included). The Decision Review inspector now opens only when a graph node is
  selected, and graph nodes are keyboard-focusable.
• Added settings dashboard (waycontext dashboard).
• Added config, integrations and restart HTTP routes (GET/PUT /v1/config, GET /v1/integrations, POST /v1/service/restart); restart is refused outside the managed service and while an index is running.
• Breaking: the managed service no longer reads a project .env. It is spawned from your home directory, without the keys a .env folded into the launching process, so its ./.env is ~/.env. Put database and embedding settings in the shell environment, the MCP registration's env, the install .env, or ~/.config/waycontext/config.json.
• Breaking: write protection on the HTTP service. Every non-GET/HEAD route (/v1/ops/*, /v1/context, /mcp and the new routes) now requires Content-Type: application/json (415 otherwise; a bodiless DELETE is exempt) and refuses a foreign Host or Origin (403).
• Honoured JSON booleans in config.json. true/false are now read as on/off; previously false left features on and true turned REASONING_AUTO_OPEN off. From the environment, true/false, yes/no and on/off (any case) are accepted alongside 1/0; any other value now falls back to the setting's default (previously anything but 0 turned most flags on, and anything but 1 turned REASONING_AUTO_OPEN off).
• waycontext service restart is honest about what it did. It prints "restarted" only after a fresh start, and exits non-zero when an unmanaged waycontext serve is answering (restart that one by hand).
• Added a settings registry (SETTINGS, settingDef) in src/config.js declaring every setting once.