agents: neighborhood placeholder, organize prompt, weight-set command

Add {{neighborhood}} placeholder for agent prompts: full seed node
content + ranked neighbors (score = link_strength * node_weight) with
smooth cutoff, minimum 10, cap 25, plus cross-links between included
neighbors.

Rewrite organize.agent prompt to focus on structural graph work:
merging duplicates, superseding junk, calibrating weights, creating
concept hubs.

Add weight-set CLI command for direct node weight manipulation.

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

poc-memory/src/agents/defs.rs

@@ -239,6 +239,7 @@ fn resolve(
         "siblings" | "neighborhood" => {
             let mut out = String::new();
             let mut all_keys: Vec<String> = Vec::new();
+            const MAX_NEIGHBORS: usize = 25;
 
             for key in keys {
                 let Some(node) = store.nodes.get(key.as_str()) else { continue };
@@ -248,35 +249,74 @@ fn resolve(
                 out.push_str(&format!("## {} (seed)\n\n{}\n\n", key, node.content));
                 all_keys.push(key.clone());
 
-                // All neighbors with full content and link strength
-                if !neighbors.is_empty() {
-                    out.push_str("### Neighbors\n\n");
-                    for (nbr, strength) in &neighbors {
+                // Rank neighbors by link_strength * node_weight
+                // Include all if <= 10, otherwise take top MAX_NEIGHBORS
+                let mut ranked: Vec<(String, f32, f32)> = neighbors.iter()
+                    .filter_map(|(nbr, strength)| {
+                        store.nodes.get(nbr.as_str()).map(|n| {
+                            let node_weight = n.weight.max(0.01);
+                            let score = strength * node_weight;
+                            (nbr.to_string(), *strength, score)
+                        })
+                    })
+                    .collect();
+                ranked.sort_by(|a, b| b.2.total_cmp(&a.2));
+
+                let total = ranked.len();
+                let included: Vec<_> = if total <= 10 {
+                    ranked
+                } else {
+                    // Smooth cutoff: threshold scales with neighborhood size
+                    // Generous — err on including too much so the agent can
+                    // see and clean up junk. 20 → top 75%, 50 → top 30%
+                    let top_score = ranked.first().map(|(_, _, s)| *s).unwrap_or(0.0);
+                    let ratio = (15.0 / total as f32).min(1.0);
+                    let threshold = top_score * ratio;
+                    ranked.into_iter()
+                        .enumerate()
+                        .take_while(|(i, (_, _, score))| *i < 10 || *score >= threshold)
+                        .take(MAX_NEIGHBORS)
+                        .map(|(_, item)| item)
+                        .collect()
+                };
+
+                if !included.is_empty() {
+                    if total > included.len() {
+                        out.push_str(&format!("### Neighbors (top {} of {}, ranked by importance)\n\n",
+                            included.len(), total));
+                    } else {
+                        out.push_str("### Neighbors\n\n");
+                    }
+                    let included_keys: std::collections::HashSet<&str> = included.iter()
+                        .map(|(k, _, _)| k.as_str()).collect();
+
+                    for (nbr, strength, _score) in &included {
                         if let Some(n) = store.nodes.get(nbr.as_str()) {
                             out.push_str(&format!("#### {} (link: {:.2})\n\n{}\n\n",
                                 nbr, strength, n.content));
                             all_keys.push(nbr.to_string());
                         }
                     }
-                }
 
-                // Cross-links between neighbors (local subgraph structure)
-                let nbr_set: std::collections::HashSet<&str> = neighbors.iter()
-                    .map(|(k, _)| k.as_str()).collect();
-                let mut cross_links = Vec::new();
-                for (nbr, _) in &neighbors {
-                    for (nbr2, strength) in graph.neighbors(nbr) {
-                        if nbr2.as_str() != key && nbr_set.contains(nbr2.as_str()) && nbr.as_str() < nbr2.as_str() {
-                            cross_links.push((nbr.clone(), nbr2, strength));
+                    // Cross-links between included neighbors
+                    let mut cross_links = Vec::new();
+                    for (nbr, _, _) in &included {
+                        for (nbr2, strength) in graph.neighbors(nbr) {
+                            if nbr2.as_str() != key
+                                && included_keys.contains(nbr2.as_str())
+                                && nbr.as_str() < nbr2.as_str()
+                            {
+                                cross_links.push((nbr.clone(), nbr2, strength));
+                            }
                         }
                     }
-                }
-                if !cross_links.is_empty() {
-                    out.push_str("### Cross-links between neighbors\n\n");
-                    for (a, b, s) in &cross_links {
-                        out.push_str(&format!("  {} ↔ {} ({:.2})\n", a, b, s));
+                    if !cross_links.is_empty() {
+                        out.push_str("### Cross-links between neighbors\n\n");
+                        for (a, b, s) in &cross_links {
+                            out.push_str(&format!("  {} ↔ {} ({:.2})\n", a, b, s));
+                        }
+                        out.push_str("\n");
                     }
-                    out.push_str("\n");
                 }
             }