feat(phase2-E): multi-provider routing via secutools delegation

Adds optional delegation of agent-queue tasks to the SecuAAS secutools
AI platform (GPU / Gemini / Claude API) instead of dispatching to a
local Claude Code tmux session. Per-task opt-in via YAML frontmatter
fields preferred_ai, allow_delegation, complexity_hint — absence keeps
the Phase 1 behaviour exactly (zero breaking change).

Go side:
- internal/secutools: HTTP client with exponential-backoff retries
  (SubmitJob/GetJob/WaitForResult), DecideProvider map adapter for CLI
  use, table tests.
- internal/router: struct-typed Decide() with strict precedence
  (needs_claude_code > preferred_ai=claude-code > allow_delegation=false
  > preferred_ai > fail-safe local on unknown).
- internal/delegation: Manager submits jobs, writes .md.delegated
  markers for on-restart recovery, runs a periodic reaper that moves
  completed jobs into done/ with provider/cost footer and failed jobs
  into failed/.
- internal/dispatcher: WithDelegation() opt-in, routeTask hook before
  findFreeSession, skips .md.delegated in assignNextTask.
- internal/api: /api/delegated/status (active jobs + counters),
  /watchdog/status extended with delegation counters.
- cmd/ccl-delegate: small CLI exposing submit/get/result/decide so the
  bash dispatcher can call the same contract without duplicating logic.
- cmd/claude-failover: delegation wired opt-in via SECUTOOLS_API_KEY.

Tests:
- 29+ new unit tests across router, secutools, delegation, dispatcher,
  api packages. go test -race -count=1 clean.
- tests/phase2-E-integration.sh: bash end-to-end against a Python
  stdlib mock HTTP server, exercising the dev-management scripts.

Forward-compat with watchdog (Phase 1 B1 already ignores
state=delegated_to_secutools) so delegated tasks aren't flagged stale.

internal/secutools/routing_test.go

@@ -0,0 +1,72 @@
+package secutools
+
+import "testing"
+
+// TestDecideProvider_TableDriven exercises the full decision matrix for
+// the map-input adapter used by the bash-side ccl-delegate CLI. The
+// richer Task-struct variant lives in internal/router.
+func TestDecideProvider_TableDriven(t *testing.T) {
+	cases := []struct {
+		name string
+		fm   map[string]any
+		want string
+	}{
+		{"nil map falls back to local", nil, "local"},
+		{"empty map → local (allow_delegation default false)", map[string]any{}, "local"},
+		{"needs_claude_code wins", map[string]any{
+			"needs_claude_code": true,
+			"allow_delegation":  true,
+			"preferred_ai":      "gpu",
+		}, "local"},
+		{"explicit claude-code stays local", map[string]any{
+			"preferred_ai":     "claude-code",
+			"allow_delegation": true,
+		}, "local"},
+		{"allow_delegation=false blocks even with preferred_ai=gpu", map[string]any{
+			"preferred_ai":     "gpu",
+			"allow_delegation": false,
+		}, "local"},
+		{"gpu", map[string]any{
+			"preferred_ai":     "gpu",
+			"allow_delegation": true,
+		}, "gpu"},
+		{"GPU (case-insensitive)", map[string]any{
+			"preferred_ai":     "GPU",
+			"allow_delegation": true,
+		}, "gpu"},
+		{"gemini", map[string]any{
+			"preferred_ai":     "gemini",
+			"allow_delegation": true,
+		}, "gemini"},
+		{"claude-api", map[string]any{
+			"preferred_ai":     "claude-api",
+			"allow_delegation": true,
+		}, "claude-api"},
+		{"auto", map[string]any{
+			"preferred_ai":     "auto",
+			"allow_delegation": true,
+		}, "auto"},
+		{"empty preferred_ai + allow_delegation → auto", map[string]any{
+			"allow_delegation": true,
+		}, "auto"},
+		{"unknown provider → fail-safe local", map[string]any{
+			"preferred_ai":     "claude-3-mystery",
+			"allow_delegation": true,
+		}, "local"},
+		{"allow_delegation as string 'true'", map[string]any{
+			"preferred_ai":     "gpu",
+			"allow_delegation": "true",
+		}, "gpu"},
+		{"allow_delegation as int 1", map[string]any{
+			"preferred_ai":     "gemini",
+			"allow_delegation": 1,
+		}, "gemini"},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if got := DecideProvider(c.fm); got != c.want {
+				t.Errorf("DecideProvider(%v) = %q, want %q", c.fm, got, c.want)
+			}
+		})
+	}
+}