fix(helm): rewrite chart with Kubernetes deployment fixes

[khalid244]

Summary

Rewrites the .helm/ chart to fix all known Kubernetes deployment issues from #119. Tested and verified on a production cluster.

Fixes

• Missing templates — adds Service, PVC, ServiceAccount, _helpers.tpl
• Ingress YAML error — host was a list instead of a scalar
• APP_KEY generation — replaces non-standard encryptAES with randAlphaNum + b64enc
• Bitnami MySQL dependency removed — built-in MySQL deployment (no external chart repos needed)
• DB startup race condition — init container waits for MySQL before app starts
• MySQL trigger migration failure — adds --log-bin-trust-function-creators=1
• MySQL startup probe — uses TCP instead of socket-based (socket doesn't exist during init)
• s6-overlay fixes — mounts /var/run, /tmp, framework/cache, framework/sessions as emptyDir
• Timeout — S6_CMD_WAIT_FOR_SERVICES_MAXTIME=300000
• TLS — cert-manager annotation support on ingress
• Values restructured — Bitnami-style with @param annotations, global.storageClass, existingClaim support

Tested on

• 3-node Hetzner cluster (MicroK8s, kubectl v1.32)
• Longhorn StorageClass
• nginx-ingress + cert-manager (Let's Encrypt)
• All 144 migrations complete successfully
• All s6 services healthy: nginx, octane, reverb, queue, supercronic
• HTTP 200 on HTTPS endpoint

Migration notes

Two Cattr migrations have duplicate table/column creation that fail on fresh installs:

1. 2020_07_21_095849_create_redmine_instances_table — table already created by 2020_06_01 migration
2. 2023_03_09_224051_upgrade_laravel_sanctum_to_3_0 — expires_at column already exists

Workaround documented in the related issue #312.

Test plan

• helm lint .helm/ passes
• helm template .helm/ renders valid YAML
• helm install on a fresh cluster deploys MySQL + Cattr
• All s6 services start without errors
• Migrations run to completion
• App accessible via ingress

Resolves #119
Related: #312