feat(role): add versioned role configs + escalation ladder + scheduler (Phase 5)

Two parts:

Part A (fixes a gap from Phase 1): Groq/OpenRouter/OpenAI were documented in
docs/api-keys-setup.md as usable once configured, but nothing actually
constructed runners for them. internal/cli/cloudrunners.go consolidates
anthropic/google/groq/openrouter/openai NativeRunner construction into one
table-driven registerCloudRunners() helper, replacing the two hand-written
per-provider blocks in serve.go/run.go. Groq/OpenRouter/OpenAI reuse
openaicompat (no new adapter code) at SandboxKind: "docker".

Part B: the token-husbanding harness's core routing mechanism.

- internal/role: RoleConfig/Tier/Rung -- a role's system prompt and a
  multi-tier (provider, model) escalation ladder, versioned via config_json.
- storage: new role_configs table (draft/active/retired, UNIQUE(role,
  version)) with transactional activate-retires-prior-active semantics;
  new executions.escalation_rung column.
- task.AgentConfig.Role string -- purely additive; every existing task shape
  (Agent.Role == "") is unaffected, proven by TestPool_Execute_NonRoleTask_Unaffected
  plus the full pre-existing suite passing unchanged.
- executor.Pool.execute(): role-typed tasks with no Agent.Type yet resolve
  tier 0 of their active ladder (round-robin across multi-candidate tiers,
  skipping rate-limited providers, falling back to soonest-clearing) before
  the existing pickAgent/Classifier path runs; SystemPrompt applies to
  Agent.SystemPromptAppend. Already-resolved role tasks (scheduler resubmits)
  get their escalation_rung re-derived read-only via findTierIndex.
- internal/scheduler: polls role-typed FAILED tasks, retries at the same
  rung under MaxRetries or escalates to the next tier's first candidate when
  budget.Accountant.Allow() permits (emitting event.KindEscalated), else
  leaves the task FAILED with a final:true KindEscalated event. An
  in-memory per-execution-ID "handled" set keeps the poll loop convergent.
  Started by `serve` only, config knob [scheduler].poll_interval_seconds.
- internal/api: POST/GET /api/roles/{role}/versions, POST
  /api/roles/{role}/activate -- unauthenticated, matching the existing
  projects/tasks REST endpoints' auth posture (only chatbot MCP, agent MCP,
  and WebSocket are api_token-gated in this codebase today).

Documented as stored-but-not-yet-enforced (CLAUDE.md Design Debt, matching
how task.Priority/RetryConfig are already documented): RoleConfig.Tools/
SandboxKind don't affect dispatch yet; DefaultBudgetUSD is read narrowly as
the scheduler's escalation cost estimate, not enforced at initial dispatch;
scheduler escalation always targets Candidates[0] (no round-robin, unlike
initial-dispatch tier-0 resolution); the scheduler's dedupe is per-process
and resets on restart (idempotent, harmless).

go build/vet/test -race -count=1 all pass, 21 packages.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V1moSNCJRcP6kykA4tyUSs

1 files changed, 151 insertions, 0 deletions

diff --git a/internal/storage/roleconfig_test.go b/internal/storage/roleconfig_test.go
new file mode 100644
index 0000000..b18eaef
--- /dev/null
+++ b/internal/storage/roleconfig_test.go
@@ -0,0 +1,151 @@
+package storage
+
+import (
+	"database/sql"
+	"errors"
+	"testing"
+)
+
+func TestCreateRoleConfig_AssignsIncrementingVersions(t *testing.T) {
+	db := testDB(t)
+
+	v1, err := db.CreateRoleConfig("coder", `{"role":"coder"}`, "human")
+	if err != nil {
+		t.Fatalf("CreateRoleConfig v1: %v", err)
+	}
+	if v1.Version != 1 {
+		t.Errorf("expected version 1, got %d", v1.Version)
+	}
+	if v1.Status != "draft" {
+		t.Errorf("expected status draft, got %q", v1.Status)
+	}
+
+	v2, err := db.CreateRoleConfig("coder", `{"role":"coder","system_prompt":"v2"}`, "human")
+	if err != nil {
+		t.Fatalf("CreateRoleConfig v2: %v", err)
+	}
+	if v2.Version != 2 {
+		t.Errorf("expected version 2, got %d", v2.Version)
+	}
+
+	// A different role starts its own version sequence at 1.
+	other, err := db.CreateRoleConfig("reviewer", `{"role":"reviewer"}`, "human")
+	if err != nil {
+		t.Fatalf("CreateRoleConfig other role: %v", err)
+	}
+	if other.Version != 1 {
+		t.Errorf("expected version 1 for a new role, got %d", other.Version)
+	}
+}
+
+func TestGetActiveRoleConfig_NoneActive_ReturnsErrNoRows(t *testing.T) {
+	db := testDB(t)
+	if _, err := db.CreateRoleConfig("coder", `{"role":"coder"}`, "human"); err != nil {
+		t.Fatalf("CreateRoleConfig: %v", err)
+	}
+	_, err := db.GetActiveRoleConfig("coder")
+	if !errors.Is(err, sql.ErrNoRows) {
+		t.Fatalf("expected sql.ErrNoRows, got %v", err)
+	}
+}
+
+func TestListRoleConfigVersions_OrderedByVersion(t *testing.T) {
+	db := testDB(t)
+	for i := 0; i < 3; i++ {
+		if _, err := db.CreateRoleConfig("coder", `{"role":"coder"}`, "human"); err != nil {
+			t.Fatalf("CreateRoleConfig: %v", err)
+		}
+	}
+	versions, err := db.ListRoleConfigVersions("coder")
+	if err != nil {
+		t.Fatalf("ListRoleConfigVersions: %v", err)
+	}
+	if len(versions) != 3 {
+		t.Fatalf("expected 3 versions, got %d", len(versions))
+	}
+	for i, v := range versions {
+		if v.Version != i+1 {
+			t.Errorf("versions[%d].Version = %d, want %d", i, v.Version, i+1)
+		}
+	}
+}
+
+// TestActivateRoleConfigVersion_ExactlyOneActive is the invariant test called
+// out in the phase spec: activating version 2 while version 1 is active must
+// atomically flip version 1 to retired.
+func TestActivateRoleConfigVersion_ExactlyOneActive(t *testing.T) {
+	db := testDB(t)
+
+	v1, err := db.CreateRoleConfig("coder", `{"role":"coder","system_prompt":"v1"}`, "human")
+	if err != nil {
+		t.Fatalf("CreateRoleConfig v1: %v", err)
+	}
+	v2, err := db.CreateRoleConfig("coder", `{"role":"coder","system_prompt":"v2"}`, "human")
+	if err != nil {
+		t.Fatalf("CreateRoleConfig v2: %v", err)
+	}
+
+	if err := db.ActivateRoleConfigVersion("coder", v1.Version); err != nil {
+		t.Fatalf("activate v1: %v", err)
+	}
+	active, err := db.GetActiveRoleConfig("coder")
+	if err != nil {
+		t.Fatalf("GetActiveRoleConfig: %v", err)
+	}
+	if active.Version != v1.Version {
+		t.Fatalf("expected active version %d, got %d", v1.Version, active.Version)
+	}
+	if active.ActivatedAt == nil {
+		t.Errorf("expected ActivatedAt to be set")
+	}
+
+	// Now activate v2 — v1 must atomically flip to retired, and v2 becomes
+	// the sole active row.
+	if err := db.ActivateRoleConfigVersion("coder", v2.Version); err != nil {
+		t.Fatalf("activate v2: %v", err)
+	}
+
+	active, err = db.GetActiveRoleConfig("coder")
+	if err != nil {
+		t.Fatalf("GetActiveRoleConfig after v2 activation: %v", err)
+	}
+	if active.Version != v2.Version {
+		t.Fatalf("expected active version %d, got %d", v2.Version, active.Version)
+	}
+
+	all, err := db.ListRoleConfigVersions("coder")
+	if err != nil {
+		t.Fatalf("ListRoleConfigVersions: %v", err)
+	}
+	activeCount := 0
+	for _, row := range all {
+		if row.Status == "active" {
+			activeCount++
+		}
+		if row.Version == v1.Version {
+			if row.Status != "retired" {
+				t.Errorf("expected v1 to be retired, got %q", row.Status)
+			}
+			if row.RetiredAt == nil {
+				t.Errorf("expected v1 RetiredAt to be set")
+			}
+		}
+	}
+	if activeCount != 1 {
+		t.Fatalf("expected exactly 1 active row, got %d", activeCount)
+	}
+}
+
+func TestActivateRoleConfigVersion_UnknownVersion_Errors(t *testing.T) {
+	db := testDB(t)
+	if _, err := db.CreateRoleConfig("coder", `{"role":"coder"}`, "human"); err != nil {
+		t.Fatalf("CreateRoleConfig: %v", err)
+	}
+	if err := db.ActivateRoleConfigVersion("coder", 99); err == nil {
+		t.Fatalf("expected error activating unknown version")
+	}
+	// No row should have been left active.
+	if _, err := db.GetActiveRoleConfig("coder"); !errors.Is(err, sql.ErrNoRows) {
+		t.Fatalf("expected sql.ErrNoRows, got %v", err)
+	}
+}