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/knowledge.rs

@@ -369,7 +369,7 @@ fn extract_conversation_text(path: &Path, max_chars: usize) -> String {
                 let text = strip_system_tags(&text);
                 if text.starts_with("[Request interrupted") { continue; }
                 if text.len() > 5 {
-                    fragments.push(format!("**Kent:** {}", text));
+                    fragments.push(format!("**{}:** {}", crate::config::get().user_name, text));
                     total += text.len();
                 }
             }
@@ -377,7 +377,7 @@ fn extract_conversation_text(path: &Path, max_chars: usize) -> String {
             if let Some(text) = extract_text_content(&obj) {
                 let text = strip_system_tags(&text);
                 if text.len() > 10 {
-                    fragments.push(format!("**PoC:** {}", text));
+                    fragments.push(format!("**{}:** {}", crate::config::get().assistant_name, text));
                     total += text.len();
                 }
             }