flatten: move poc-memory contents to workspace root

No more subcrate nesting — src/, agents/, schema/, defaults/, build.rs
all live at the workspace root. poc-daemon remains as the only workspace
member. Crate name (poc-memory) and all imports unchanged.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/lib.rs

@@ -0,0 +1,43 @@
+// poc-memory library — unified crate for memory graph + agent infrastructure
+//
+// Merged from poc-memory + poc-agent. Single crate, no circular deps.
+
+// Agent infrastructure (formerly poc-agent)
+pub mod agent;
+
+// Core infrastructure
+pub mod config;
+pub mod store;
+pub mod util;
+pub mod graph;
+pub mod query;
+pub mod similarity;
+pub mod spectral;
+pub mod lookups;
+// search was moved into query/engine
+pub use query::engine as search;
+// old query.rs moved into query/parser
+pub use query::parser as query_parser;
+pub mod transcript;
+pub mod neuro;
+pub mod counters;
+pub mod cursor;
+
+// CLI handlers (split from main.rs)
+pub mod cli;
+
+// Agent layer (LLM-powered operations)
+pub mod agents;
+pub mod tui;
+
+// Re-export agent submodules at crate root for backwards compatibility
+pub use agents::{
+    llm, audit, consolidate, knowledge,
+    enrich, digest, daemon,
+};
+
+pub mod memory_search;
+
+pub mod memory_capnp {
+    include!(concat!(env!("OUT_DIR"), "/schema/memory_capnp.rs"));
+}