test(mcp): smoke the okf 1.1 server through the run's own MCP path -- works by full path, not by bare name

A new test builds a small invented collection with `okf build` and connects through
load_mcp_config -> build_mcp_tools -> async with. No model call, no network. It measures:
- the four tools are offered, and a narrower allowed_tools narrows them;
- okf_list names the collection;
- okf_ask returns the excerpt.

That holds only when the config gives the full path to okf 1.1. With the README's bare `okf`,
a run under `uv run` or an activated venv finds this project's own dependency
llm-ingestion-okf 0.8.5 first. That version has no `mcp` subcommand, and the server fails at
startup ("invalid choice: 'mcp'"). This is pinned as xfail(strict=True, raises=ToolException)
and not repaired, per the order.

The tests skip when no okf >= 1.1.0 is found on PATH outside the venv. The version is measured
from the server's own initialize answer. README limits now state what was measured. The
published-surface pin moves from 518 to 519 for the new file.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -390,9 +390,13 @@ With it, the server and each allowed tool are named in the announcement before t
 
 **Limits, stated plainly.**
 
-- The link between this framework and the `okf` server has **not been tried in a real run**. Only
-  the config file is validated (`tests/test_okf_server_example.py`, against the same loader a run
-  uses).
+- **Measured without a model** (`tests/test_okf_server_smoke.py`, against a small invented
+  collection): through the same loader and tool builder a run uses, `okf` 1.1 offers exactly the
+  four tools, `allowed_tools` narrows what is offered, `okf_list` names the collection and one
+  `okf_ask` returns the excerpt. **This works only when `command` is the full path to the `okf`
+  1.1 executable.** With the bare `okf` shown above, a run started with `uv run` or from an
+  activated environment finds this framework's own `okf` dependency (0.8.5) first. That version
+  has no `mcp` command, and the server fails at startup (`invalid choice: 'mcp'`).
 - It is **not measured** whether the agents follow the way of working the server describes.
 - `--prepass-payload` does not accept the v1.1 format (`okf-consumption/2`). That is a known gap.