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>

poc-memory/agents/distill.agent

@@ -1,29 +0,0 @@
-{"agent":"distill","query":"all | type:semantic | sort:degree | limit:1","model":"sonnet","schedule":"daily"}
-
-{{node:core-personality}}
-
-{{node:memory-instructions-core}}
-
-## Here's your seed node, and its siblings:
-
-{{neighborhood}}
-
-{{node:memory-instructions-core-subconscious}}
-
-{{node:subconscious-notes-{agent_name}}}
-
-## Your task
-
-Organize and refine the seed node, pulling in knowledge from its neighbors.
-
-- **Update the seed node** with new insights from sibling nodes
-- **Create new nodes** if you find related concepts that deserve their own place
-- **Organize connections** — create sub-concepts if there are too many links on different topics
-- **Move knowledge up or down** in the graph to make it well organized
-- **Calibrate links** — use existing link strengths as references
-- **Knowledge flows upward** — raw experiences enrich topic nodes, not the reverse
-- **Integrate, don't summarize** — the node should grow by absorbing what was learned
-- **Respect the existing voice** — don't rewrite in a generic tone
-- **Formative experiences are load-bearing** — keep the moments that shaped understanding
-- **When in doubt, link don't rewrite** — adding a connection is safer than rewriting
-- **Fix connections** — if links are missing or miscalibrated, fix them