chore(warden): Reduce review cost and use Luna auxiliary calls (#209)

Cut org-wide Warden spend by dropping default effort from max to high
and ignoring docs, tests, fixtures, and snapshot paths that security
review still paid to analyze.

---------

Co-authored-by: sentry-junior[bot] <264270552+sentry-junior[bot]@users.noreply.github.com>
Co-authored-by: David Cramer <david@sentry.io>

Author: sentry-junior[bot]

warden.toml

@@ -3,14 +3,41 @@ version = 1
 [defaults]
 runtime = "pi"
 model = "openrouter/x-ai/grok-4.5"
-effort = "max"
 reportOn = "low"
 failOn = "off"
 failCheck = false
 requestChanges = false
+# Skip low-signal paths for all skills. Security review still pays to analyze
+# files even when the skill prompt would not report findings on them.
+# Note: Warden globs do not expand brace patterns.
+ignorePaths = [
+  "**/*.md",
+  "**/*.mdx",
+  "**/docs/**",
+  "**/CHANGELOG*",
+  "**/README*",
+  "**/tests/**",
+  "**/test/**",
+  "**/__tests__/**",
+  "**/__mocks__/**",
+  "**/e2e/**",
+  "**/fixtures/**",
+  "**/*.test.*",
+  "**/*.spec.*",
+  "**/test_*.py",
+  "**/*_test.py",
+  "**/*_test.go",
+  "**/*.snap",
+  "**/migrations/meta/**",
+  "**/*_snapshot.json",
+]
+
+[defaults.agent]
+effort = "high"
 
 [defaults.auxiliary]
-model = "openrouter/moonshotai/kimi-k2.6"
+model = "openrouter/openai/gpt-5.6-luna"
+effort = "high"
 
 [[skills]]
 name = "security-review"