Rebuild AgentRunSupervisor on go.gearno.de/kit/worker

The supervisor was a hand-rolled polling, semaphore, and wait-group
loop predating the project's adoption of the shared worker kit. Two
sibling workers in pkg/probo already use the kit, and go-worker.md
documents it as the project convention.

This commit introduces agentRunHandler, which implements
worker.Handler[coredata.AgentRun] and worker.StaleRecoverer, and
reduces AgentRunSupervisor to a thin wrapper that owns the handler
plus a worker.Worker and bridges ctx cancellation into a handler-
level shutdown broadcast via context.AfterFunc. The agent stop
channel is now closed by a per-Process forwarder goroutine when the
broadcast fires, so in-flight runs checkpoint at the next turn
boundary and drain through wg.Wait before Run returns.

The stop_requested column, struct field, supporting SQL, and the
LoadRunningStopRequestedIDs function are removed end-to-end. None
of it was ever wired to an external surface; it existed purely to
let the supervisor find runs the operator wanted to halt. With the
kit handling the polling cadence and the AfterFunc bridging
shutdown, per-row flagging is dead weight.

The supervisor's public API (NewAgentRunSupervisor, Run, the With*
option helpers, and the error sentinels) stays intact so probod.go
needs no change. The integration test now triggers stop by
cancelling the supervisor context, which is the actual production
path through SIGTERM rather than a synthetic DB flag. Prometheus
counters and OTel spans labelled worker="agent-run-supervisor"
come for free.

Signed-off-by: Aurélien Sibiril <81782+aureliensibiril@users.noreply.github.com>

pkg/coredata/agent_run.go

@@ -41,7 +41,6 @@ type (
 		InputMessages  json.RawMessage `db:"input_messages"`
 		Result         json.RawMessage `db:"result"`
 		ErrorMessage   *string         `db:"error_message"`
-		StopRequested  bool            `db:"stop_requested"`
 		StartedAt      *time.Time      `db:"started_at"`
 		LeaseOwner     *string         `db:"lease_owner"`
 		LeaseExpiresAt *time.Time      `db:"lease_expires_at"`
@@ -111,7 +110,6 @@ SELECT
 	input_messages,
 	result,
 	error_message,
-	stop_requested,
 	started_at,
 	lease_owner,
 	lease_expires_at,
@@ -164,7 +162,6 @@ SELECT
 	input_messages,
 	result,
 	error_message,
-	stop_requested,
 	started_at,
 	lease_owner,
 	lease_expires_at,
@@ -219,7 +216,6 @@ SELECT
 	input_messages,
 	result,
 	error_message,
-	stop_requested,
 	started_at,
 	lease_owner,
 	lease_expires_at,
@@ -317,7 +313,6 @@ RETURNING
 	input_messages,
 	result,
 	error_message,
-	stop_requested,
 	started_at,
 	lease_owner,
 	lease_expires_at,
@@ -362,7 +357,6 @@ SET
 	status = @status,
 	result = @result,
 	error_message = @error_message,
-	stop_requested = @stop_requested,
 	started_at = @started_at,
 	lease_owner = @lease_owner,
 	lease_expires_at = @lease_expires_at,
@@ -379,7 +373,6 @@ RETURNING
 	input_messages,
 	result,
 	error_message,
-	stop_requested,
 	started_at,
 	lease_owner,
 	lease_expires_at,
@@ -394,7 +387,6 @@ RETURNING
 		"status":           e.Status,
 		"result":           e.Result,
 		"error_message":    e.ErrorMessage,
-		"stop_requested":   e.StopRequested,
 		"started_at":       e.StartedAt,
 		"lease_owner":      e.LeaseOwner,
 		"lease_expires_at": e.LeaseExpiresAt,
@@ -481,7 +473,6 @@ RETURNING
 	input_messages,
 	result,
 	error_message,
-	stop_requested,
 	started_at,
 	lease_owner,
 	lease_expires_at,
@@ -526,7 +517,6 @@ SELECT
 	input_messages,
 	result,
 	error_message,
-	stop_requested,
 	started_at,
 	lease_owner,
 	lease_expires_at,
@@ -536,7 +526,6 @@ FROM
 	agent_runs
 WHERE
 	status = 'PENDING'
-	AND stop_requested = false
 ORDER BY created_at ASC
 LIMIT 1
 FOR UPDATE SKIP LOCKED;
@@ -564,8 +553,7 @@ FOR UPDATE SKIP LOCKED;
 // The worker refreshes lease_expires_at from a separate heartbeat goroutine,
 // so a long LLM or tool call is not considered stale while the process is alive.
 // Stale recovery returns rows to PENDING so the supervisor auto-resumes
-// from checkpoint when one exists. User-requested suspension remains
-// SUSPENDED and is resumed only by the Resume service method.
+// from checkpoint when one exists.
 func ResetStaleAgentRuns(ctx context.Context, conn pg.Querier) error {
 	q := `
 UPDATE agent_runs
@@ -574,7 +562,6 @@ SET
 	started_at = NULL,
 	lease_owner = NULL,
 	lease_expires_at = NULL,
-	stop_requested = false,
 	updated_at = now()
 WHERE
 	status = 'RUNNING'
@@ -624,33 +611,6 @@ WHERE
 	return tag.RowsAffected(), nil
 }
 
-// LoadRunningStopRequestedIDs returns IDs of running agent runs with
-// stop_requested = true.
-func LoadRunningStopRequestedIDs(ctx context.Context, conn pg.Querier) ([]string, error) {
-	q := `SELECT id FROM agent_runs WHERE status = 'RUNNING' AND stop_requested = true;`
-
-	rows, err := conn.Query(ctx, q)
-	if err != nil {
-		return nil, fmt.Errorf("cannot query stop-requested agent runs: %w", err)
-	}
-	defer rows.Close()
-
-	var ids []string
-	for rows.Next() {
-		var id string
-		if err := rows.Scan(&id); err != nil {
-			return nil, fmt.Errorf("cannot scan stop-requested agent run ID: %w", err)
-		}
-		ids = append(ids, id)
-	}
-
-	if err := rows.Err(); err != nil {
-		return nil, fmt.Errorf("cannot iterate stop-requested agent runs: %w", err)
-	}
-
-	return ids, nil
-}
-
 // PGCheckpointer implements agent.Checkpointer backed by the
 // agent_runs table checkpoint column. It is supervisor-internal and
 // intentionally uses raw run IDs with no tenant scope; public service/API

pkg/coredata/migrations/20260424T120000Z.sql

@@ -22,7 +22,6 @@ CREATE TABLE agent_runs (
     input_messages  JSONB NOT NULL,
     result          JSONB,
     error_message   TEXT,
-    stop_requested  BOOLEAN NOT NULL DEFAULT FALSE,
     started_at      TIMESTAMPTZ,
     lease_owner     TEXT,
     lease_expires_at TIMESTAMPTZ,