feat: add FlareSolverr proxy support with DB-backed config

- Add config table for storing FlareSolverr proxy setting
- Add HTTP endpoints to get/set proxy status (GET/POST /api/config/flaresolverr)
- Refactor httpclient to support proxy mode (requests go through FlareSolverr)
- Add verbose logging for debugging
- Add POST support to FlareSolverr client

Usage:
  GET /api/config/flaresolverr - returns {flaresolverr_proxy: bool}
  POST /api/config/flaresolverr - body: {enabled: true/false}

Makefile

@@ -1,4 +1,5 @@
-DEV_COMPOSE = docker compose -f compose-dev.yml --env-file dev.env
+DEV_COMPOSE = docker compose -f compose-dev.yml
+DEV_GO = /usr/local/go/bin/go
 
 .PHONY: dev-up dev-shell dev-down dev-logs dev-build dev-run smoke-keyoapp-plain smoke-keyoapp-plain-dev
 
@@ -25,4 +26,4 @@ smoke-keyoapp-plain:
 
 smoke-keyoapp-plain-dev:
 	$(DEV_COMPOSE) up -d postgres flaresolverr dev
-	$(DEV_COMPOSE) exec dev sh -lc "GOYOMI_SMOKE=1 go test -count=1 -v ./sources -run TestStandaloneKeyoappSmoke"
+	$(DEV_COMPOSE) exec dev sh -lc "GOYOMI_SMOKE=1 $(DEV_GO) test -count=1 -v ./sources -run TestStandaloneKeyoappSmoke"