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/app/app.go

@@ -14,6 +14,7 @@ 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"
@@ -56,6 +57,7 @@ type Deps struct {
 	Consolidation *consolidation.Service
 	Reflection    *reflection.Service
 	Graph         *graph.Store
+	Capabilities  *capabilities.Service
 	LLM           *router.Router
 	LLMStore      *router.Store
 	Prompts       *prompts.Store