security: add the capability and policy layer as the only path to action

Phase 12 (ADR-0005). Capabilities are registered in code with parameter
schemas, risk classes and default effects; sudo_shell and delete_database
are locked to DENY and cannot be relaxed. Policies are scoped globally or
per mind with capability, target glob, action kind and optional hour
window; evaluation is deterministic, most specific wins, and ties go to
the stricter effect. Invoke is the single entry point: it refuses
dreaming and replay contexts, validates parameters (unknown keys, non
http URLs and path traversal rejected), evaluates policy and session
grants, hashes the exact request and records a policy_decision event.
ALLOW executes with timeout and panic isolation and turns textual output
into a tool-trust observation; ASK creates an approval request bound to
the hash with an alert notification; DENY is counted and recorded.

Operators approve once, approve for a time-boxed session grant, deny
with a note, or modify parameters (re-validated, re-hashed, original
kept in the append-only decision log). The self-model's capability list
is recomputed from effective policy on start and on every policy change.
The act process maps fetch requests to http.fetch and the action handler
invokes through the layer; replies report capabilities and outcomes.

Policy matrix and approval centre pages, dashboard count, API, CLI
(approvals, policy, invoke) and docs/capabilities.md.

internal/api/api_test.go

@@ -15,6 +15,7 @@ import (
 	"github.com/andydixon/noema/internal/auth"
 	"github.com/andydixon/noema/internal/beliefs"
 	"github.com/andydixon/noema/internal/brain"
+	"github.com/andydixon/noema/internal/capabilities"
 	"github.com/andydixon/noema/internal/config"
 	"github.com/andydixon/noema/internal/consolidation"
 	"github.com/andydixon/noema/internal/conversation"
@@ -51,6 +52,11 @@ func testServer(t *testing.T) (*httptest.Server, string) {
 	ctx := context.Background()
 	deps.Resolver = &predictions.Resolver{Store: deps.Predictions, Events: deps.Events, Beliefs: deps.Beliefs, Log: log}
 	deps.Graph = graph.NewStore(pool)
+	capReg := capabilities.NewRegistry()
+	for _, c := range capabilities.Builtins() {
+		capReg.Add(c)
+	}
+	deps.Capabilities = &capabilities.Service{Registry: capReg, DB: pool, Events: deps.Events, Log: log}
 	deps.Narrative = narrative.NewStore(pool)
 	deps.Notifications = notifications.NewStore(pool)
 	deps.Consolidation = &consolidation.Service{DB: pool, Memory: deps.Memory, Beliefs: deps.Beliefs, Events: deps.Events, Minds: deps.Minds, Log: log}