feat: import OpenAPI and GraphQL specs as MCP tools

[daltoniam]

Summary

• Adds a "bring your own spec" feature: paste an OpenAPI 3.x document or a GraphQL introspection result and its operations become searchable, executable MCP tools — no adapter code required.
• New management page in the web UI (list / add / remove) with live status, plus live reload so imported tools appear without restarting the server.

How it works

• New specimport/ package parses a spec into a runtime Integration (Load), and a Syncer reconciles the registry against config on startup and on every config change — it only ever touches integrations it registered, never built-ins.
• Imports are stored in config under spec_imports and injected server-side credentials never reach the model.

Fixes bundled in

Two bugs discovered during live testing that made imported tools invisible to search/execute even though they showed as active in the UI:

1. Config loading silently dropped imports on every read (they weren't carried through the defaults merge).
2. The enabled-integration lookup used by search indexing and execute resolution didn't include imports.

Verification

Tested end-to-end against the live Swagger Petstore: search returns the imported tools and execute performs real upstream calls (valid IDs return data, invalid IDs return the upstream 404). Full CI passes (build, vet, race tests, lint).

💘 Generated with Crush

[acmacalister]

CI/status checks all passing (build, test, lint, security). Clean PR — follows project conventions, comprehensive test coverage, no blocking issues found. LGTM.