p3: harvest 28 bake-off queries with targets and blind protocol

Kyle-approved fleet harvest. Sibling targets (domain/page or open).
Runner labels A-D; mapping stays in a sealed key file until scoring.

tests/testdata/search_targets.txt

@@ -0,0 +1,31 @@
+# Sibling of search_queries.txt. Line N (ignoring this comment and blanks) is the
+# target for query N. A good result set must contain this page or domain.
+# `open` means no required hit — score usefulness only.
+docs.firecrawl.dev
+docs.tavily.com
+brave.com
+docs.vllm.ai
+a2a-protocol.org
+hermes-agent.nousresearch.com
+docs.anthropic.com
+journals.plos.org
+arxiv.org
+arxiv.org/abs/2609.13781
+arxiv.org
+github.com/bitsandbytes-foundation
+open
+nvidia.com
+open
+frame.work
+huggingface.co
+asus.com
+msi.com
+cubemars.com
+sandisk.com
+docs.vllm.ai
+github.com/vrtmrz/obsidian-livesync
+omarchy.org
+huggingface.co
+huggingface.co
+huggingface.co
+github.com/bendlang/bend