Extract lib.rs, inline search in memory-search hook

Create lib.rs so all binaries can share library code directly instead
of shelling out to poc-memory. memory-search now calls search::search()
and store::Store::load() in-process instead of Command::new("poc-memory").

The load-context call still shells out (needs get_group_content moved
from main.rs to a library module).

Also: add search::format_results(), deduplicate extract_query_terms.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/lib.rs

@@ -0,0 +1,28 @@
+// poc-memory library — shared modules for all binaries
+//
+// Re-exports modules so that memory-search and other binaries
+// can call library functions directly instead of shelling out.
+
+pub mod config;
+pub mod store;
+pub mod util;
+pub mod llm;
+pub mod digest;
+pub mod audit;
+pub mod enrich;
+pub mod consolidate;
+pub mod graph;
+pub mod search;
+pub mod similarity;
+pub mod migrate;
+pub mod neuro;
+pub mod query;
+pub mod spectral;
+pub mod lookups;
+pub mod daemon;
+pub mod fact_mine;
+pub mod knowledge;
+
+pub mod memory_capnp {
+    include!(concat!(env!("OUT_DIR"), "/schema/memory_capnp.rs"));
+}