chore: sort __slots__ tuples alphabetically (ruff RUF023)

[alexzhu0]

Summary

Ruff rule RUF023 flags __slots__ tuples that are not in natural-sort order. Python itself doesn't care about slot order — slots are addressed by name, not position — but keeping them sorted makes diffs trivially reviewable and removes a class of copy-paste-then-miss-one-field bugs.

10 occurrences across 9 files, all auto-fixable.

What changed

Pure reordering. No slot is added, removed, renamed, or rewired. No __init__, descriptor lookup, __reduce__/pickle protocol, or inheritance contract changes.

 class CacheDBInterface(ABC):
     ...
-    __slots__ = ("_host", "_port", "_key", "_lock")
+    __slots__ = ("_host", "_key", "_lock", "_port")

 class FastembedEmbeddingEngine(EmbeddingEngine):
     ...
     __slots__ = (
-        "model",
-        "dimensions",
-        "max_completion_tokens",
         "batch_size",
+        "dimensions",
         "embedding_model",
-        "tokenizer",
+        "max_completion_tokens",
         "mock",
+        "model",
+        "tokenizer",
     )

Files

Area	Classes
Cache interface	CacheDBInterface
Embedding engines	FastembedEmbeddingEngine, OllamaEmbeddingEngine
Graph primitives	MemoryGraph, MemoryGraphNode, MemoryGraphEdge (2 classes in MemoryGraphElements.py)
Tokenizer adapters	GeminiTokenizer, MistralTokenizer
Pipeline / IO	Stage (pipeline/tasks/task.py), FileBufferedReader

9 files, +16 / −16.

Verification

$ ruff check . --exclude 'm_flow/baml_client' --exclude 'm_flow-frontend' --select RUF023
All checks passed!

$ for mod in m_flow.adapters.cache.cache_db_interface \
             m_flow.knowledge.graph_ops.m_flow_graph.MemoryGraph \
             m_flow.pipeline.tasks.task \
             m_flow.shared.files.storage.FileBufferedReader; do
    PYTHONPATH=. uv run python -c "import $mod"
  done
# import ok: all modules

No behavior change. Generated code under m_flow/baml_client/ is untouched.

I affirm that all code in every commit of this pull request conforms to the terms of the M-flow Developer Certificate of Origin

[alexzhu0]

Static analysis — weighted-edge sources failing here (and on every fork PR) is not from this change — it's a workflow config bug. The job's ruff-action args pass m_flow/knowledge/graph_ops/** as a string; ruff-action doesn't shell-expand it, so ruff hits E902 No such file or directory on the literal ** path before it lints anything.

I've opened #167 with a two-line fix (drop /**, ruff recurses into directories). Once that merges this check should go green on this PR without any rebase here.

(The other failing checks are already green after the latest push.)