Phase 005: vendor ArkScope, land the Arco style baseline, and fix bridge interpreter resolution

- Vendor ArkScope decorative layers (ScrambleTitle / IsometricWave) with provenance notes; decorative-only per AGENTS.md red lines
- Migrate theme tokens to Arco, register the Arco theme, and add hook adapter composables (useMessage / useDialog / useNotification) with matching signatures
- Sample pages: LoginView and AppSidebar on the new baseline; docs/arco-mapping.md and docs/ui-baseline.md land
- agent-bridge: prefer the PM-selected venv from facts.json over legacy in-tree venvs (legacy lacks the mcp extra, so every MCP server showed 0 tools / not connected)
- agent-bridge python (vendored, deliberate deviation): MCP discovery import fallback and pyyaml -> hermes_yaml so plugins and MCP work under the PM env; install the mcp extra via `hermes pm install --extra mcp`
- Chat-chain fragment: docs/chat-chain-changes/2026-10-17-phase005-arkscope-baseline.md

Verified: harness:check, test (2020 passed), test:e2e (30 passed), build all green; manual: plugins 100/0 warnings, MCP 6/6 servers connected with 104 tools.

AGENTS.md

@@ -56,6 +56,10 @@ Use the smallest relevant check while iterating. Before a broad PR, run
   `services/hermes/context-engine/` are the chat chain: changes require a
   `docs/chat-chain-changes/<date>-<slug>.md` fragment.
 - `packages/desktop` and `packages/website` are removed; do not reintroduce them.
+- ArkScope vendor (`packages/client/src/vendor/arkscore/`) is decorative only:
+  login-page title, Journey graph background, first-load / empty states. Never in
+  chat, forms, tables, or click-dense areas. Decorative layers must be
+  `pointer-events: none` and carry no information or interaction.
 
 ## When The Agent Gets Stuck