poc-memory agent run: single agent execution with dry-run

New command: `poc-memory agent run <agent> [--count N] [--dry-run]`

Runs a single agent by name through the full pipeline (build prompt,
call LLM, apply actions). With --dry-run, sets POC_MEMORY_DRY_RUN=1
so all mutations are no-ops but the agent can still read the graph.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

poc-memory/src/cli/agent.rs

@@ -5,6 +5,19 @@ use crate::store::StoreView;
 use crate::agents::llm;
 use std::sync::atomic::{AtomicUsize, Ordering};
 
+pub fn cmd_run_agent(agent: &str, count: usize, dry_run: bool) -> Result<(), String> {
+    if dry_run {
+        std::env::set_var("POC_MEMORY_DRY_RUN", "1");
+    }
+    let mut store = store::Store::load()?;
+    let log = |msg: &str| eprintln!("[{}] {}", agent, msg);
+    let (total, applied) = crate::agents::knowledge::run_and_apply_with_log(
+        &mut store, agent, count, "test", &log,
+    )?;
+    eprintln!("[{}] {} actions, {} applied", agent, total, applied);
+    Ok(())
+}
+
 pub fn cmd_consolidate_batch(count: usize, auto: bool, agent: Option<String>) -> Result<(), String> {
     let store = store::Store::load()?;
 

poc-memory/src/main.rs

@@ -558,6 +558,17 @@ enum AgentCmd {
         /// Path to JSONL transcript
         path: String,
     },
+    /// Run a single agent by name
+    Run {
+        /// Agent name (e.g. observation, linker, distill)
+        agent: String,
+        /// Batch size (number of seed nodes/fragments)
+        #[arg(long, default_value_t = 5)]
+        count: usize,
+        /// Dry run — set POC_MEMORY_DRY_RUN=1 so mutations are no-ops
+        #[arg(long)]
+        dry_run: bool,
+    },
     /// Show spaced repetition replay queue
     #[command(name = "replay-queue")]
     ReplayQueue {
@@ -800,6 +811,8 @@ fn main() {
             AgentCmd::FactMine { path, batch, dry_run, output, min_messages }
                 => cli::agent::cmd_fact_mine(&path, batch, dry_run, output.as_deref(), min_messages),
             AgentCmd::FactMineStore { path } => cli::agent::cmd_fact_mine_store(&path),
+            AgentCmd::Run { agent, count, dry_run }
+                => cli::agent::cmd_run_agent(&agent, count, dry_run),
             AgentCmd::ReplayQueue { count } => cli::agent::cmd_replay_queue(count),
             AgentCmd::Evaluate { matchups, model, dry_run }
                 => cli::agent::cmd_evaluate_agents(matchups, &model, dry_run),