feat(mem0-plugin): expand categories to 17, add recall rubric + confidence + files tagging

Tier 5 implementation:
- #17: Expand coding categories from 7 to 17 (dependency_decisions,
  performance_findings, security_constraints, testing_patterns, data_model,
  api_contracts, deployment_runbook, team_norms, domain_glossary,
  experiment_results)
- #18: Category-recall rubric table in mem0-mcp/SKILL.md mapping user
  intent to 2-3 categories for parallel search fan-out
- #19: metadata.confidence scoring rules (1.0/0.8/0.5/0.3 scale)
- #20: metadata.files array tagging for affected file paths

mem0-plugin/tests/test_coding_categories.py

@@ -0,0 +1,88 @@
+"""Tests for setup_coding_categories.py -- CODING_CATEGORIES list completeness."""
+
+from __future__ import annotations
+
+import importlib
+import os
+import sys
+
+import pytest
+
+SCRIPTS_DIR = os.path.join(os.path.dirname(__file__), "..", "scripts")
+
+EXPECTED_KEYS = [
+    "architecture_decisions",
+    "anti_patterns",
+    "task_learnings",
+    "tooling_setup",
+    "bug_fixes",
+    "coding_conventions",
+    "user_preferences",
+    "dependency_decisions",
+    "performance_findings",
+    "security_constraints",
+    "testing_patterns",
+    "data_model",
+    "api_contracts",
+    "deployment_runbook",
+    "team_norms",
+    "domain_glossary",
+    "experiment_results",
+]
+
+
+@pytest.fixture()
+def coding_categories():
+    """Import CODING_CATEGORIES from setup_coding_categories, ensuring scripts/ is on path."""
+    abs_scripts = os.path.abspath(SCRIPTS_DIR)
+    inserted = False
+    if abs_scripts not in sys.path:
+        sys.path.insert(0, abs_scripts)
+        inserted = True
+    # Force re-import in case another test already loaded a stale version
+    mod_name = "setup_coding_categories"
+    if mod_name in sys.modules:
+        del sys.modules[mod_name]
+    mod = importlib.import_module(mod_name)
+    yield mod.CODING_CATEGORIES
+    if inserted and abs_scripts in sys.path:
+        sys.path.remove(abs_scripts)
+
+
+def test_total_count(coding_categories):
+    """CODING_CATEGORIES must contain exactly 17 entries."""
+    assert len(coding_categories) == 17, (
+        f"Expected 17 categories, found {len(coding_categories)}: "
+        f"{[list(c.keys())[0] for c in coding_categories]}"
+    )
+
+
+def test_all_expected_keys_present(coding_categories):
+    """Every expected category key must appear exactly once."""
+    actual_keys = [list(cat.keys())[0] for cat in coding_categories]
+    for key in EXPECTED_KEYS:
+        assert key in actual_keys, f"Missing expected category key: '{key}'"
+
+
+def test_no_duplicate_keys(coding_categories):
+    """No category key may appear more than once."""
+    actual_keys = [list(cat.keys())[0] for cat in coding_categories]
+    seen = set()
+    duplicates = []
+    for key in actual_keys:
+        if key in seen:
+            duplicates.append(key)
+        seen.add(key)
+    assert not duplicates, f"Duplicate category keys found: {duplicates}"
+
+
+def test_each_description_is_non_empty_string(coding_categories):
+    """Every category must have a non-empty string description."""
+    for cat in coding_categories:
+        assert len(cat) == 1, f"Category dict should have exactly one key, got: {cat}"
+        key = list(cat.keys())[0]
+        description = cat[key]
+        assert isinstance(description, str), (
+            f"Category '{key}' description is not a string: {type(description)}"
+        )
+        assert description.strip(), f"Category '{key}' has an empty description"