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/config.rs

@@ -0,0 +1,93 @@
+// Configuration for poc-memory
+//
+// Loaded from ~/.config/poc-memory/config.toml (or POC_MEMORY_CONFIG env).
+// Falls back to sensible defaults if no config file exists.
+
+use std::path::PathBuf;
+use std::sync::OnceLock;
+
+static CONFIG: OnceLock<Config> = OnceLock::new();
+
+#[derive(Debug, Clone)]
+pub struct Config {
+    /// Display name for the human user in transcripts/prompts.
+    pub user_name: String,
+    /// Display name for the AI assistant.
+    pub assistant_name: String,
+    /// Base directory for memory data (store, logs, status).
+    pub data_dir: PathBuf,
+    /// Directory containing Claude session transcripts.
+    pub projects_dir: PathBuf,
+    /// Core node keys that should never be decayed/deleted.
+    pub core_nodes: Vec<String>,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        let home = PathBuf::from(std::env::var("HOME").expect("HOME not set"));
+        Self {
+            user_name: "User".to_string(),
+            assistant_name: "Assistant".to_string(),
+            data_dir: home.join(".claude/memory"),
+            projects_dir: home.join(".claude/projects"),
+            core_nodes: vec!["identity.md".to_string()],
+        }
+    }
+}
+
+impl Config {
+    fn load_from_file() -> Self {
+        let path = std::env::var("POC_MEMORY_CONFIG")
+            .map(PathBuf::from)
+            .unwrap_or_else(|_| {
+                PathBuf::from(std::env::var("HOME").expect("HOME not set"))
+                    .join(".config/poc-memory/config.toml")
+            });
+
+        let mut config = Config::default();
+
+        let Ok(content) = std::fs::read_to_string(&path) else {
+            return config;
+        };
+
+        // Simple TOML parser — we only need flat key = "value" pairs.
+        for line in content.lines() {
+            let line = line.trim();
+            if line.is_empty() || line.starts_with('#') {
+                continue;
+            }
+            let Some((key, value)) = line.split_once('=') else { continue };
+            let key = key.trim();
+            let value = value.trim().trim_matches('"');
+
+            match key {
+                "user_name" => config.user_name = value.to_string(),
+                "assistant_name" => config.assistant_name = value.to_string(),
+                "data_dir" => config.data_dir = expand_home(value),
+                "projects_dir" => config.projects_dir = expand_home(value),
+                "core_nodes" => {
+                    config.core_nodes = value.split(',')
+                        .map(|s| s.trim().to_string())
+                        .filter(|s| !s.is_empty())
+                        .collect();
+                }
+                _ => {}
+            }
+        }
+
+        config
+    }
+}
+
+fn expand_home(path: &str) -> PathBuf {
+    if let Some(rest) = path.strip_prefix("~/") {
+        PathBuf::from(std::env::var("HOME").expect("HOME not set")).join(rest)
+    } else {
+        PathBuf::from(path)
+    }
+}
+
+/// Get the global config (loaded once on first access).
+pub fn get() -> &'static Config {
+    CONFIG.get_or_init(Config::load_from_file)
+}