Preserve operator config across OpenAPI re-imports (#6)

[keysersoft]

Problem

Importing a spec twice into the same connector created tools on the first run and silently skipped on the second (`P2002` swallow in `createToolsFromParsed`). Two consequences:

• Operator customisations made between imports — custom `responseMapping`, manual `isEnabled: false` — were lost on the next re-import.
• Endpoints that disappeared from upstream stayed registered forever, with no signal they were stale. Role assignments pointed at zombie tools.

Fix

Turn `createToolsFromParsed` into a reconciliation step.

Schema (additive, nullable; no backfill needed)

```
mcp_tools.operation_id TEXT
mcp_tools.deprecated_at TIMESTAMP(3)
```

Parser

`ParsedTool.operationId` is populated from the source operation when present (works for 3.0 and 3.1).

Reconciliation

1. Snapshot existing tools.
2. For each parsed tool, look up by operationId first, fall back to (method, path).
3. Match → `UPDATE` in place. Preserves `responseMapping` unless the spec declares a new one. Preserves the operator's manual `isEnabled` toggle. Clears `deprecatedAt` if previously set.
4. No match → `CREATE`.
5. Snapshot entries unmatched by any parsed tool get `deprecatedAt = now()` + `isEnabled = false`. They stay in the DB so `ToolRoleAccess` and invocation history survive.

Response shape

```json
{
"message": "Imported tools: created N, updated N, deprecated N",
"tools": [...],
"created": N,
"updated": N,
"deprecated": ["tool_name_1", ...],
"skipped": [] // kept for back-compat; always empty now
}
```

Frontend

Tool list shows a yellow `deprecated` badge next to the existing `enabled`/`disabled` pill, with a tooltip showing the date the tool fell off the spec.

Test plan

• Parser spec asserts `operationId` is preserved on `ParsedTool` (new test in `openapi.parser.spec.ts`).
• Full backend test suite green: 631 passed across 26 suites.
• `tsc --noEmit` clean on backend and frontend.
• After deploy: import spec → assign role → re-import same spec → role still on tool. Re-import a modified spec that drops one endpoint → tool gets `deprecated` badge, role assignment intact.