feat: connect local Obsidian vaults to conversations

Users can now read, search, and update existing local Obsidian notes through
built-in tools without configuring an external MCP server or Obsidian plugin.
Add vault discovery, an optional folder scope, and independent test, save,
enablement, and runtime assignment controls in MCP settings.

Bundle MCPVault 0.16.0 and its runtime dependencies, exposing 19 shared tools
to direct models and managed local OpenCode and Continue conversations.
Obsidian is disabled by default. Ask remains read-only; Execute permits
writes. Scope and assignment changes revoke existing Obsidian grants.
DeepSeek Harness and remote execution remain unsupported.

Validate the isolated staged snapshot with its own dependency installation:
typecheck, lint, production build, and 540 tests across 14 files passed.
No paid model calls were repeated. Physical-offline, installer, and other
platform acceptance remain pending as documented in the feature record.

Release note: Connect local Obsidian vaults in MCP settings to find notes and
write conversation results back to them. Test all registered vaults or a
chosen folder before enabling access; no Obsidian plugin is required.

FEATURES.md

@@ -581,6 +581,17 @@ records are listed separately and do not introduce another feature status.
   DeepSeek Harness unsupported. Built-in MCP uses short-lived local authority
   for the current request, and user configuration cannot loosen Ask/Execute
   read/write boundaries.
+- **Obsidian integration (implemented in source, acceptance in progress)**:
+  Disabled by default, with all locally registered vaults as the default scope
+  and an optional folder that can be tested before saving or enabling.
+  Bundled MCPVault 0.16.0 provides all upstream abilities through 19 shared tools.
+  Automated production-component checks, Electron managed-Node tests, Windows
+  settings and chat UI checks, and restricted-network Windows x64 unpacked-app
+  checks passed. Physical-offline, installer, and other-platform acceptance
+  remain pending. DeepSeek
+  Harness and remote execution remain unavailable. See the
+  [feature docs and validation record](./docs/features/obsidian/README.md);
+  this is not a release claim.
 - [x] **MCP Tools**: Explicitly enabled custom MCP can be assigned to direct
   models, GoodBuddy-managed OpenCode, Continue Agent Execute, and DeepSeek
   Harness, and loads only in Execute. Agent child processes receive only