Migrate from Gin to Echo framework and add comprehensive integration tests

Major changes:
- Migrate all handlers from Gin to Echo framework
- Add new apperrors, echohelpers, and validator packages
- Update middleware for Echo compatibility
- Add ArchivedHandler to task categorization chain (archived tasks go to cancelled_tasks column)
- Add 6 new integration tests:
  - RecurringTaskLifecycle: NextDueDate advancement for weekly/monthly tasks
  - MultiUserSharing: Complex sharing with user removal
  - TaskStateTransitions: All state transitions and kanban column changes
  - DateBoundaryEdgeCases: Threshold boundary testing
  - CascadeOperations: Residence deletion cascade effects
  - MultiUserOperations: Shared residence collaboration
- Add single-purpose repository functions for kanban columns (GetOverdueTasks, GetDueSoonTasks, etc.)
- Fix RemoveUser route param mismatch (userId -> user_id)
- Fix determineExpectedColumn helper to correctly prioritize in_progress over overdue

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

go.mod

@@ -3,13 +3,13 @@ module github.com/treytartt/casera-api
 go 1.24.0
 
 require (
-	github.com/gin-contrib/cors v1.7.3
-	github.com/gin-gonic/gin v1.10.1
+	github.com/go-playground/validator/v10 v10.23.0
 	github.com/golang-jwt/jwt/v5 v5.3.0
 	github.com/google/uuid v1.6.0
 	github.com/gorilla/websocket v1.5.3
 	github.com/hibiken/asynq v0.25.1
 	github.com/jung-kurt/gofpdf v1.16.2
+	github.com/labstack/echo/v4 v4.11.4
 	github.com/nicksnyder/go-i18n/v2 v2.6.0
 	github.com/redis/go-redis/v9 v9.17.1
 	github.com/rs/zerolog v1.34.0
@@ -32,24 +32,19 @@ require (
 	cloud.google.com/go/auth v0.17.0 // indirect
 	cloud.google.com/go/auth/oauth2adapt v0.2.8 // indirect
 	cloud.google.com/go/compute/metadata v0.9.0 // indirect
-	github.com/bytedance/sonic v1.14.0 // indirect
-	github.com/bytedance/sonic/loader v0.3.0 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
-	github.com/cloudwego/base64x v0.1.6 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
 	github.com/felixge/httpsnoop v1.0.4 // indirect
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.8 // indirect
-	github.com/gin-contrib/sse v1.1.0 // indirect
 	github.com/go-logr/logr v1.4.3 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-ole/go-ole v1.2.6 // indirect
 	github.com/go-playground/locales v0.14.1 // indirect
 	github.com/go-playground/universal-translator v0.18.1 // indirect
-	github.com/go-playground/validator/v10 v10.23.0 // indirect
 	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
-	github.com/goccy/go-json v0.10.5 // indirect
+	github.com/golang-jwt/jwt v3.2.2+incompatible // indirect
 	github.com/golang-jwt/jwt/v4 v4.5.2 // indirect
 	github.com/google/s2a-go v0.1.9 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.3.7 // indirect
@@ -60,15 +55,12 @@ require (
 	github.com/jackc/puddle/v2 v2.2.2 // indirect
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.5 // indirect
-	github.com/json-iterator/go v1.1.12 // indirect
-	github.com/klauspost/cpuid/v2 v2.3.0 // indirect
+	github.com/labstack/gommon v0.4.2 // indirect
 	github.com/leodido/go-urn v1.4.0 // indirect
 	github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-sqlite3 v2.0.3+incompatible // indirect
-	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
-	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c // indirect
@@ -82,15 +74,14 @@ require (
 	github.com/subosito/gotenv v1.6.0 // indirect
 	github.com/tklauser/go-sysconf v0.3.12 // indirect
 	github.com/tklauser/numcpus v0.6.1 // indirect
-	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
-	github.com/ugorji/go/codec v1.3.0 // indirect
+	github.com/valyala/bytebufferpool v1.0.0 // indirect
+	github.com/valyala/fasttemplate v1.2.2 // indirect
 	github.com/yusufpapurcu/wmi v1.2.4 // indirect
 	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.61.0 // indirect
 	go.opentelemetry.io/otel v1.38.0 // indirect
 	go.opentelemetry.io/otel/metric v1.38.0 // indirect
 	go.opentelemetry.io/otel/trace v1.38.0 // indirect
-	golang.org/x/arch v0.12.0 // indirect
 	golang.org/x/net v0.47.0 // indirect
 	golang.org/x/sync v0.18.0 // indirect
 	golang.org/x/sys v0.38.0 // indirect