render: show links footer for graph walkability; query: full --help

render now appends a links section showing up to 15 neighbors as
copy-pasteable `poc-memory render` commands, making the graph
naturally walkable without memorizing node keys.

query --help now documents the full language: expressions, fields,
operators, pipe stages, functions, and examples. Inline help in
cmd_query replaced with pointer to --help.

poc-memory/src/main.rs

@@ -116,8 +116,49 @@ enum Command {
     /// Summary of memory state
     Status,
     /// Query the memory graph
+    #[command(after_long_help = "\
+EXPRESSIONS:
+  *                                all nodes
+  key ~ 'pattern'                  regex match on node key
+  content ~ 'phrase'               regex match on node content
+  degree > 15                      numeric comparison on any field
+  field = value                    exact match
+  field != value                   not equal
+  expr AND expr                    boolean AND
+  expr OR expr                     boolean OR
+  NOT expr                         negation
+  neighbors('key')                 nodes linked to key
+  neighbors('key') WHERE expr      ... with filter on edges/nodes
+
+FIELDS:
+  key, weight, content, degree, node_type, provenance,
+  emotion, retrievals, uses, wrongs, created,
+  clustering_coefficient (cc), community_id
+
+OPERATORS:
+  >  <  >=  <=  =  !=  ~(regex)
+
+PIPE STAGES:
+  | sort FIELD [asc]               sort (desc by default)
+  | limit N                        cap results
+  | select F,F,...                 output fields as TSV
+  | count                          just show count
+
+FUNCTIONS:
+  community('key')                 community id of a node
+  degree('key')                    degree of a node
+
+EXAMPLES:
+  key ~ 'inner-life'                         substring match on keys
+  content ~ 'made love'                      full-text search
+  degree > 15 | sort degree | limit 10       high-degree nodes
+  key ~ 'journal' AND degree > 10 | count    count matching nodes
+  neighbors('identity') WHERE strength > 0.5 | sort strength
+  * | sort weight asc | limit 20             lowest-weight nodes
+  node_type = semantic | sort degree         all semantic nodes by degree
+")]
     Query {
-        /// Query expression (e.g. "degree > 15 | sort degree | limit 10")
+        /// Query expression (e.g. "key ~ 'inner-life'")
         expr: Vec<String>,
     },
     /// Mark a memory as useful (boosts weight)
@@ -2048,6 +2089,32 @@ fn cmd_render(key: &[String]) -> Result<(), String> {
         .ok_or_else(|| format!("Node not found: {}", bare))?;
 
     print!("{}", node.content);
+
+    // Show links so the graph is walkable
+    let mut neighbors: Vec<(&str, f32)> = Vec::new();
+    for r in &store.relations {
+        if r.deleted { continue; }
+        if r.source_key == bare {
+            neighbors.push((&r.target_key, r.strength));
+        } else if r.target_key == bare {
+            neighbors.push((&r.source_key, r.strength));
+        }
+    }
+    if !neighbors.is_empty() {
+        neighbors.sort_by(|a, b| b.1.partial_cmp(&a.1).unwrap_or(std::cmp::Ordering::Equal));
+        neighbors.dedup_by(|a, b| a.0 == b.0);
+        let total = neighbors.len();
+        let shown: Vec<_> = neighbors.iter().take(15)
+            .map(|(k, _)| format!("`poc-memory render {}`", k))
+            .collect();
+        print!("\n\n---\nLinks:");
+        for link in &shown {
+            println!("\n  {}", link);
+        }
+        if total > 15 {
+            println!("  ... and {} more (`poc-memory graph link {}`)", total - 15, bare);
+        }
+    }
     Ok(())
 }
 
@@ -2434,17 +2501,7 @@ fn cmd_interference(threshold: f32) -> Result<(), String> {
 
 fn cmd_query(expr: &[String]) -> Result<(), String> {
     if expr.is_empty() {
-        return Err("query requires an expression\n\n\
+        return Err("query requires an expression (try: poc-memory query --help)".into());
-Expressions:\n  \
-  degree > 15                          property filter\n  \
-  key ~ 'journal.*' AND degree > 10    boolean + regex\n  \
-  neighbors('identity') WHERE ...   graph traversal\n  \
-  *                                    all nodes\n\n\
-Pipe stages:\n  \
-  | sort FIELD [asc]    sort (desc by default)\n  \
-  | limit N             cap results\n  \
-  | select F,F,...      output fields as TSV\n  \
-  | count               just show count".into());
     }
 
     let query_str = expr.join(" ");