cli: add homelab edges — who-talks-to-whom investigation helper (v0.9.0)

Makes the goldmane_edges east-west trail (ADR-0014) reachable during incident
investigations without remembering the DB/creds/SQL. New top-level verb:

  homelab edges --ns <ns>         edges touching <ns> (either direction)
  homelab edges --src/--dst <ns>  directional egress / ingress peers
  homelab edges --peers-of <ns>   distinct peer namespaces of <ns>
  homelab edges --new-since 24h   first seen since a duration or date (YYYY-MM-DD)
  homelab edges --denied          only action='deny' (blocked / lateral movement)
  homelab edges --json --limit N  machine-readable / row cap (default 200)

Filters render to a single read-only SELECT against the `edge` table, run via
the dbaas CNPG primary pod (same exec path as `k8s db`). Namespace values are
validated to the k8s name charset (injection guard) before they reach SQL.

TDD: edges_test.go covers flag parsing, query building (each filter, AND
combination, peers-of shape, JSON wrapper), the new-since duration/date parser,
and namespace-validation / injection rejection. Smoke-tested live: --peers-of,
--new-since 24h, --denied, and --json all return correct rows.

Docs: runbook query section now leads with the CLI; cli/README gains a v0.9
section. VERSION v0.8.2 -> v0.9.0.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

cli/cmd_edges.go

@@ -0,0 +1,69 @@
+package main
+
+import "fmt"
+
+func edgesCommands() []Command {
+	return []Command{
+		{Path: []string{"edges"}, Tier: TierRead,
+			Summary: "who-talks-to-whom trail: edges [--ns|--src|--dst|--peers-of N] [--new-since 24h] [--denied] [--json] [--limit N]",
+			Run:     edgesRun},
+	}
+}
+
+// edgesRun renders the filter flags to SQL and runs it read-only against the
+// goldmane_edges CNPG DB via the dbaas primary pod (same exec path as `k8s db`).
+func edgesRun(args []string) error {
+	for _, a := range args {
+		if a == "-h" || a == "--help" {
+			fmt.Print(edgesUsage())
+			return nil
+		}
+	}
+	o, err := parseEdgesArgs(args)
+	if err != nil {
+		return fmt.Errorf("%w\n\n%s", err, edgesUsage())
+	}
+	sql, err := buildEdgesQuery(o)
+	if err != nil {
+		return err
+	}
+	// pg-cluster-rw is a Service (not exec-able); resolve the primary POD.
+	pod, err := kubectlCapture("dbaas", "get", "pod", "-l", "cnpg.io/instanceRole=primary",
+		"-o", "jsonpath={.items[0].metadata.name}")
+	if err != nil || pod == "" {
+		return fmt.Errorf("could not resolve CNPG primary pod in dbaas: %v", err)
+	}
+	exec := []string{"exec", pod, "-c", "postgres", "--", "psql", "-U", "postgres", "-d", "goldmane_edges"}
+	if o.asJSON {
+		exec = append(exec, "-tAc", sql) // raw tuple → the JSON array
+	} else {
+		exec = append(exec, "-P", "pager=off", "-c", sql) // aligned table for humans
+	}
+	return kubectlStream("dbaas", exec...)
+}
+
+func edgesUsage() string {
+	return `homelab edges — query the who-talks-to-whom trail (goldmane_edges, ADR-0014)
+
+Usage: homelab edges [filters]
+
+Filters (AND-combined; namespace values are validated to the k8s name charset):
+  --ns NAME         edges touching NAME (either direction)
+  --src NAME        edges where source namespace = NAME
+  --dst NAME        edges where destination namespace = NAME
+  --peers-of NAME   distinct peer namespaces of NAME (both directions)
+  --new-since SPEC  first seen since SPEC: a duration (24h, 7d, 30m, 90s) or a date (YYYY-MM-DD)
+  --denied          only denied (action='deny') edges — blocked / lateral-movement attempts
+  --json            output a JSON array (for agents/pipelines)
+  --limit N         cap rows (default 200)
+
+Examples:
+  homelab edges --ns immich                # everything immich talks to / is talked to by
+  homelab edges --peers-of authentik       # authentik's peer namespaces
+  homelab edges --src recruiter-responder  # that namespace's egress peers
+  homelab edges --new-since 24h            # edges first seen in the last day
+  homelab edges --denied --json            # blocked flows, machine-readable
+
+Read-only SELECT against CNPG DB goldmane_edges via the dbaas primary pod.
+`
+}