Exclude docs from ai-sources, mention ai-sources in CLAUDE.md

ai-sources now skips docs/ to avoid duplicating ai-docs output.
CLAUDE.md notes ai-sources as available for deep context on problems
with a large surface area.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

mise-tasks/ai-sources

@@ -12,6 +12,7 @@ git -C "$ROOT" ls-files \
   | grep -v '\.gitkeep$' \
   | grep -v '\.gitattributes$' \
   | grep -v '^LICENSE$' \
+  | grep -v '^docs/' \
   | while read -r f; do
       printf '=== %s ===\n' "$f"
       cat "$ROOT/$f"