restructure: hippocampus/ for memory, subconscious/ for agents

hippocampus/ — memory storage, retrieval, and consolidation:
  store, graph, query, similarity, spectral, neuro, counters,
  config, transcript, memory_search, lookups, cursor, migrate

subconscious/ — autonomous agents that process without being asked:
  reflect, surface, consolidate, digest, audit, etc.

All existing crate::X paths preserved via re-exports in lib.rs.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

src/hippocampus/mod.rs

@@ -0,0 +1,20 @@
+// hippocampus — memory storage, retrieval, and consolidation
+//
+// The graph-structured memory system: nodes, relations, queries,
+// similarity scoring, spectral analysis, and neuroscience-inspired
+// consolidation (spaced repetition, interference detection, schema
+// assimilation).
+
+pub mod store;
+pub mod graph;
+pub mod lookups;
+pub mod cursor;
+pub mod query;
+pub mod similarity;
+pub mod spectral;
+pub mod neuro;
+pub mod counters;
+pub mod migrate;
+pub mod config;
+pub mod transcript;
+pub mod memory_search;