chore: initialize EverOS 1.0.0

md-first memory extraction framework for AI agents.

Markdown is the single source of truth; SQLite holds state and LanceDB
provides the rebuildable vector + BM25 + scalar index. The codebase follows
a single-direction DDD layering (entrypoints -> service -> memory -> infra,
with component / core / config cross-cutting) enforced by import-linter.

Engineering surface:
- Coding conventions in .claude/rules/ (path-scoped) and workflows in
  .claude/skills/ (/commit, /new-branch, /pr).
- GitHub Actions CI runs make lint + test + integration; pre-commit mirrors
  the gates locally (ruff, hygiene hooks, gitlint commit-msg).
- Commit messages follow Conventional Commits, enforced by gitlint.
- make lint also enforces datetime two-zone discipline and OpenAPI drift.

src/everos/core/observability/metrics/counter.py

@@ -0,0 +1,50 @@
+"""Counter wrapper around ``prometheus_client.Counter``."""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+from typing import Any
+
+from prometheus_client import Counter as PromCounter
+
+from .registry import get_metrics_registry
+
+
+class Counter:
+    """Monotonically-increasing counter (totals, error counts)."""
+
+    def __init__(
+        self,
+        name: str,
+        description: str,
+        labelnames: Sequence[str] = (),
+        namespace: str = "",
+        subsystem: str = "",
+        unit: str = "",
+    ) -> None:
+        self._counter = PromCounter(
+            name=name,
+            documentation=description,
+            labelnames=labelnames,
+            namespace=namespace,
+            subsystem=subsystem,
+            unit=unit,
+            registry=get_metrics_registry(),
+        )
+        self._labelnames = tuple(labelnames)
+
+    def labels(self, **labels: str) -> LabeledCounter:
+        return LabeledCounter(self._counter.labels(**labels))
+
+    def inc(self, amount: float = 1.0) -> None:
+        self._counter.inc(amount)
+
+
+class LabeledCounter:
+    """Counter slice with labels applied."""
+
+    def __init__(self, labeled: Any) -> None:
+        self._labeled = labeled
+
+    def inc(self, amount: float = 1.0) -> None:
+        self._labeled.inc(amount)