refactor(api): restructured API for type safety, maintainability and docs generation

- These changes makes the API incombatible with previous versions
- Added new types for error handling, success responses, and health checks.
- Updated health check logic to utilize the new types for better clarity and structure.
- Refactored existing handlers to improve response consistency and error handling.
- Updated Makefile to include a new target for generating API types from Swagger.
- Updated "new agent" API to respond an encrypted cert pair

internal/api/v1/metrics/upime.go

@@ -0,0 +1,34 @@
+package metrics
+
+import (
+	"github.com/gin-gonic/gin"
+	"github.com/yusing/go-proxy/internal/metrics/period"
+	"github.com/yusing/go-proxy/internal/metrics/uptime"
+)
+
+type UptimeRequest struct {
+	Limit    int           `query:"limit" example:"10"`
+	Offset   string        `query:"offset" example:"10"`
+	Interval period.Filter `query:"interval" example:"1m"`
+	Keyword  string        `query:"keyword" example:""`
+} // @name UptimeRequest
+
+type UptimeAggregate period.ResponseType[uptime.Aggregated] // @name UptimeAggregate
+
+// @x-id				"uptime"
+// @BasePath		/api/v1
+// @Summary		Get uptime
+// @Description	Get uptime
+// @Tags			metrics,websocket
+// @Produce   json
+// @Param			request	query		UptimeRequest	false	"Request"
+// @Success		200		{object}	uptime.StatusByAlias "no period specified"
+// @Success		200		{object}	UptimeAggregate "period specified"
+// @Success   204   {object}	apitypes.ErrorResponse
+// @Failure		400		{object}	apitypes.ErrorResponse
+// @Failure		403		{object}	apitypes.ErrorResponse
+// @Failure		500		{object}	apitypes.ErrorResponse
+// @Router			/metrics/uptime [get]
+func Uptime(c *gin.Context) {
+	uptime.Poller.ServeHTTP(c)
+}