feat(m1): attribute vocab + sampling (T1.2)

- ATTRIBUTE_VOCAB (16 AIOps channels w/ units)
- FREQ_BANDS (6 sampling resolutions)
- sample_attributes(n_channels, seed) -> unique-name, reproducible
- tests/test_attributes.py (8 tests, RED->GREEN)

Exit criteria: fields complete, count correct, seed-reproducible.

src/tsmm/data/attributes.py

@@ -0,0 +1,77 @@
+"""Variable attribute vocabulary + attribute sampling (T1.2).
+
+Defines a curated vocabulary of AIOps-relevant channel *names* with their
+*units* and a set of *sampling frequency bands*. ``sample_attributes`` draws a
+reproducible, unique-name subset to describe the channels of a multivariate
+series — metadata that the instruction generator and the multimodal splicer
+will later turn into text tokens like ``[属性: CPU usage (%), 1s]``.
+"""
+
+from __future__ import annotations
+
+import random
+from typing import Any
+
+# ─── vocabulary ────────────────────────────────────────────────────────────
+# Each entry: name (human label), unit. Frequencies are drawn separately from
+# FREQ_BANDS so the same channel name can appear at different resolutions.
+ATTRIBUTE_VOCAB: list[dict[str, str]] = [
+    {"name": "CPU usage", "unit": "%"},
+    {"name": "Memory usage", "unit": "%"},
+    {"name": "Disk I/O", "unit": "MB/s"},
+    {"name": "Network inbound traffic", "unit": "Mbps"},
+    {"name": "Network outbound traffic", "unit": "Mbps"},
+    {"name": "Request rate", "unit": "req/s"},
+    {"name": "Request latency p50", "unit": "ms"},
+    {"name": "Request latency p99", "unit": "ms"},
+    {"name": "Error rate", "unit": "%"},
+    {"name": "Temperature", "unit": "°C"},
+    {"name": "Queue length", "unit": "tasks"},
+    {"name": "Active connections", "unit": "conn"},
+    {"name": "Cache hit ratio", "unit": "%"},
+    {"name": "GPU utilization", "unit": "%"},
+    {"name": "Battery level", "unit": "%"},
+    {"name": "Pod restart count", "unit": "count"},
+]
+
+# Sampling frequency bands (resolution at which the series is recorded).
+FREQ_BANDS: list[str] = ["1s", "5s", "10s", "30s", "1min", "5min"]
+
+
+def sample_attributes(
+    n_channels: int, *, seed: int | None = None
+) -> list[dict[str, Any]]:
+    """Sample ``n_channels`` distinct channel attribute descriptors.
+
+    Each descriptor is a dict with keys ``name``, ``unit`` (drawn from
+    :data:`ATTRIBUTE_VOCAB`) and ``freq`` (drawn from :data:`FREQ_BANDS`).
+    Channel names are guaranteed unique within the returned list.
+
+    Parameters
+    ----------
+    n_channels:
+        Number of channels to sample. Must be ``<= len(ATTRIBUTE_VOCAB)``.
+    seed:
+        RNG seed for reproducibility.
+
+    Raises
+    ------
+    ValueError
+        If ``n_channels`` exceeds the available distinct names.
+    """
+    if not isinstance(n_channels, int) or n_channels < 0:
+        raise ValueError(f"n_channels must be a non-negative int, got {n_channels!r}")
+    if n_channels > len(ATTRIBUTE_VOCAB):
+        raise ValueError(
+            f"requested {n_channels} channels but vocab only has "
+            f"{len(ATTRIBUTE_VOCAB)} distinct names"
+        )
+
+    rng = random.Random(seed)
+    vocab = list(ATTRIBUTE_VOCAB)
+    chosen = rng.sample(vocab, n_channels)
+    freqs = rng.choices(FREQ_BANDS, k=n_channels)
+    return [
+        {"name": c["name"], "unit": c["unit"], "freq": f}
+        for c, f in zip(chosen, freqs)
+    ]