feat: implement boundary usage tracker and telemetry collection (#21716)

Implements telemetry for boundary usage tracking across all Coder
replicas and reports them via telemetry.

Changes:
- Implement Tracker with Track(), FlushToDB(), and StartFlushLoop() methods
- Add telemetry integration via collectBoundaryUsageSummary()
- Use telemetry lock to ensure only one replica collects per period

The tracker accumulates unique workspaces, unique users, and request
counts (allowed/denied) in memory, then flushes to the database
periodically. During telemetry collection, stats are aggregated across
all replicas and reset for the next period.

coderd/agentapi/api.go

@@ -20,6 +20,7 @@ import (
 	"github.com/coder/coder/v2/coderd/agentapi/metadatabatcher"
 	"github.com/coder/coder/v2/coderd/agentapi/resourcesmonitor"
 	"github.com/coder/coder/v2/coderd/appearance"
+	"github.com/coder/coder/v2/coderd/boundaryusage"
 	"github.com/coder/coder/v2/coderd/connectionlog"
 	"github.com/coder/coder/v2/coderd/database"
 	"github.com/coder/coder/v2/coderd/database/pubsub"
@@ -87,6 +88,7 @@ type Options struct {
 	PublishWorkspaceUpdateFn          func(ctx context.Context, userID uuid.UUID, event wspubsub.WorkspaceEvent)
 	PublishWorkspaceAgentLogsUpdateFn func(ctx context.Context, workspaceAgentID uuid.UUID, msg agentsdk.LogsNotifyMessage)
 	NetworkTelemetryHandler           func(batch []*tailnetproto.TelemetryEvent)
+	BoundaryUsageTracker              *boundaryusage.Tracker
 
 	AccessURL                 *url.URL
 	AppHostname               string
@@ -224,10 +226,12 @@ func New(opts Options, workspace database.Workspace) *API {
 	}
 
 	api.BoundaryLogsAPI = &BoundaryLogsAPI{
-		Log:               opts.Log,
-		WorkspaceID:       opts.WorkspaceID,
-		TemplateID:        workspace.TemplateID,
-		TemplateVersionID: opts.TemplateVersionID,
+		Log:                  opts.Log,
+		WorkspaceID:          opts.WorkspaceID,
+		OwnerID:              opts.OwnerID,
+		TemplateID:           workspace.TemplateID,
+		TemplateVersionID:    opts.TemplateVersionID,
+		BoundaryUsageTracker: opts.BoundaryUsageTracker,
 	}
 
 	// Start background cache refresh loop to handle workspace changes