config file, install command, scrub personal references

Add ~/.config/poc-memory/config.toml for user_name, assistant_name,
data_dir, projects_dir, and core_nodes. All agent prompts and
transcript parsing now use configured names instead of hardcoded
personal references.

`poc-memory daemon install` writes the systemd user service and
installs the memory-search hook into Claude's settings.json.

Scrubbed hardcoded names from code and docs.

Authors: ProofOfConcept <poc@bcachefs.org> and Kent Overstreet

src/store/ops.rs

@@ -210,7 +210,8 @@ impl Store {
     /// Bulk recategorize nodes using rule-based logic.
     /// Returns (changed, unchanged) counts.
     pub fn fix_categories(&mut self) -> Result<(usize, usize), String> {
-        let core_files = ["identity.md", "kent.md"];
+        let cfg = crate::config::get();
+        let core_files: Vec<&str> = cfg.core_nodes.iter().map(|s| s.as_str()).collect();
         let tech_files = [
             "language-theory.md", "zoom-navigation.md",
             "rust-conversion.md", "poc-architecture.md",