feat: add the relationship graph with extraction, corrections and explorer

Phase 11. Entities are mind-scoped nodes with canonical matching,
aliases and deterministic kind guessing (hostnames and hyphenated ids
are systems, capitalised names people, file suffixes documents).
Relationships carry a relation from the shared vocabulary, confidence,
source, reinforcement count and the event that produced them; links tie
entities to memories, beliefs, events, goals and predictions.

The perceive and attend handlers upsert the entities a message or
observation mentions and record co-mention edges cited to the event, so
the graph grows only from what was actually seen. Operators can merge
("these are the same": edges and links move, the old name becomes an
alias, the old id still resolves), record that two entities are
different, correct kinds and add typed edges; every correction is an
operator action and a corrections row.

The explorer renders a bounded subgraph on a canvas with a small
force-directed layout in plain JavaScript, with kind filters, focus on
a neighbourhood and a side panel per entity. API, entity page, CLI and
docs/graph.md.

cmd/noemactl/graph.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/url"
+	"os"
+	"strings"
+	"text/tabwriter"
+)
+
+func init() {
+	extraCommands = append(extraCommands, command{"entity", "list <mind> [query]|inspect <mind> <id>|merge <mind> <id> <other>|distinct <mind> <id> <other> – relationship graph", cmdEntity})
+}
+
+func cmdEntity(args []string) int {
+	if len(args) < 2 {
+		fmt.Fprintln(os.Stderr, "usage: noemactl entity list <mind> [query] | inspect <mind> <id> | merge <mind> <id> <other> | distinct <mind> <id> <other>")
+		return exitUsage
+	}
+	mind := args[1]
+	switch args[0] {
+	case "list":
+		q := ""
+		if len(args) > 2 {
+			q = "?q=" + url.QueryEscape(strings.Join(args[2:], " "))
+		}
+		var out struct{ Items []map[string]any }
+		if code, err := apiRequest("GET", "/api/v1/minds/"+mind+"/entities"+q, nil, &out); err != nil {
+			return exitFor(code, err)
+		}
+		tw := tabwriter.NewWriter(os.Stdout, 0, 4, 2, ' ', 0)
+		fmt.Fprintln(tw, "KIND\tNAME\tMENTIONS\tID")
+		for _, e := range out.Items {
+			fmt.Fprintf(tw, "%v\t%v\t%v\t%v\n", e["kind"], e["name"], e["mention_count"], e["id"])
+		}
+		tw.Flush()
+		return exitOK
+	case "inspect":
+		if len(args) < 3 {
+			return exitUsage
+		}
+		var d map[string]any
+		if code, err := apiRequest("GET", "/api/v1/minds/"+mind+"/entities/"+args[2], nil, &d); err != nil {
+			return exitFor(code, err)
+		}
+		enc := json.NewEncoder(os.Stdout)
+		enc.SetIndent("", "  ")
+		enc.Encode(d) //nolint:errcheck
+		return exitOK
+	case "merge", "distinct":
+		if len(args) < 4 {
+			return exitUsage
+		}
+		var d map[string]any
+		if code, err := apiRequest("POST", "/api/v1/minds/"+mind+"/entities/"+args[2]+"/"+args[0], map[string]any{"other": strings.Join(args[3:], " ")}, &d); err != nil {
+			return exitFor(code, err)
+		}
+		fmt.Println(args[0], "recorded")
+		return exitOK
+	}
+	return exitUsage
+}