feat(story,scheduler): add epic-proposal tool + AskUser-timeout escalation (Phase 7c)

Two independent pieces, completing Phase 7.

Epic-proposal tool: AgentChannel gains a 5th method, ProposeEpic(ctx,
EpicProposal{Name, Description, StoryIDs}) (epicID, err), implemented on
storeChannel -- matches an existing epic by exact name or creates one
(DiscoverySource: "agent"), sets epic_id on each resolvable story (skips,
doesn't fail, on an unresolved ID), emits KindEpicProposed attached to the
epic's own ID with payload {epic_id, name, story_ids}. Wired into both
transports exactly like Phase 6 wired role into spawn_subtask: a new
propose_epic tool in the native tool-use loop (internal/agentloop/tools.go)
and the MCP transport (internal/executor/agentmcp.go). This is the mechanism
for a discovery/planner-role agent to act on its own judgment that several
stories it's been given form one cohesive initiative -- the judgment itself
lives in the calling agent's instructions/model, not in this code.

AskUser-timeout escalation: extends the existing Scheduler (Phase 5's
retry-then-escalate watcher) rather than adding a new component, since
"stuck task needs escalation" is exactly what it already does. Finds
role-typed BLOCKED tasks whose question has been outstanding longer than
SchedulerConfig.AskUserTimeoutSeconds (default 10 minutes) using
task.UpdatedAt as the outstanding-since timestamp -- no new column needed,
since UpdateTaskQuestion already stamps it the instant a question is
recorded and nothing else touches the row while BLOCKED. Resolves the next
ladder tier from the latest execution's EscalationRung, records the
system-authored fallback answer as an audit-trail task.Interaction, clears
the question, sets the new tasks.needs_review flag, emits KindEscalated
(now carrying a trigger field: "failure" vs "ask_user_timeout" for the
existing failure-retry path vs this one), and resumes via Pool.SubmitResume
at the escalated tier -- degrading to same-tier resume with final:true if
the ladder's exhausted or no role config exists, since unblocking the task
takes priority over having somewhere higher to escalate to.
GET /api/tasks?needs_review=true surfaces auto-decided tasks for human
review.

go build/vet/test -race -count=1 all pass, full suite (20 packages), run
twice to rule out flakiness in the new tests. (One pre-existing, unrelated
test -- TestHandleRunTask_CascadesRetryToFailedDeps, a tempdir-cleanup race
-- appeared once under full-suite load per the implementing agent's report
and did not reproduce in this verification's runs either; not a regression
from this work.)

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

1 files changed, 36 insertions, 5 deletions

diff --git a/internal/executor/agentmcp_test.go b/internal/executor/agentmcp_test.go
index 4aeb7cb..c73d6db 100644
--- a/internal/executor/agentmcp_test.go
+++ b/internal/executor/agentmcp_test.go
@@ -12,11 +12,13 @@ import (
 
 // recordingChannel is a fake AgentChannel that records tool invocations.
 type recordingChannel struct {
-	asked    string
-	summary  string
-	spawned  []SubtaskSpec
-	progress []string
-	spawnID  string
+	asked         string
+	summary       string
+	spawned       []SubtaskSpec
+	progress      []string
+	spawnID       string
+	proposedEpics []EpicProposal
+	epicID        string
 }
 
 func (c *recordingChannel) AskUser(_ context.Context, q string) (string, error) {
@@ -35,6 +37,10 @@ func (c *recordingChannel) RecordProgress(_ context.Context, m string) error {
 	c.progress = append(c.progress, m)
 	return nil
 }
+func (c *recordingChannel) ProposeEpic(_ context.Context, spec EpicProposal) (string, error) {
+	c.proposedEpics = append(c.proposedEpics, spec)
+	return c.epicID, nil
+}
 
 func resultText(t *testing.T, res *mcp.CallToolResult) string {
 	t.Helper()
@@ -178,6 +184,31 @@ func TestAgentServer_RecordProgress(t *testing.T) {
 	}
 }
 
+func TestAgentServer_ProposeEpic(t *testing.T) {
+	ch := &recordingChannel{epicID: "epic-1"}
+	cs := connectInMemory(t, newAgentServer(ch))
+	res, err := cs.CallTool(context.Background(), &mcp.CallToolParams{
+		Name:      "propose_epic",
+		Arguments: map[string]any{"name": "Checkout revamp", "description": "relaunch", "story_ids": []string{"s1", "s2"}},
+	})
+	if err != nil {
+		t.Fatalf("CallTool: %v", err)
+	}
+	if len(ch.proposedEpics) != 1 {
+		t.Fatalf("expected 1 proposed epic, got %d", len(ch.proposedEpics))
+	}
+	spec := ch.proposedEpics[0]
+	if spec.Name != "Checkout revamp" || spec.Description != "relaunch" {
+		t.Errorf("epic spec not propagated: %+v", spec)
+	}
+	if len(spec.StoryIDs) != 2 || spec.StoryIDs[0] != "s1" || spec.StoryIDs[1] != "s2" {
+		t.Errorf("story_ids not propagated: %+v", spec.StoryIDs)
+	}
+	if txt := resultText(t, res); !strings.Contains(txt, "epic-1") {
+		t.Errorf("expected returned epic ID in result, got %q", txt)
+	}
+}
+
 type bearerRT struct {
 	token string
 	base  http.RoundTripper