feat(gitea): Migrate configuration from environment variables to app.ini

- Move all Gitea configuration from docker-compose.yml environment variables to app.ini
- Enable Redis cache with proper connection string format (redis://)
- Fix Redis password to use Gitea Redis instance password (gitea_redis_password) instead of application Redis stack password
- Add database connection pool settings to prevent timeout errors
- Configure Redis for cache, session, and queue using app.ini
- Update Ansible task to use correct Redis password for Gitea Redis instance

Benefits:
- Cache now works correctly (environment variables had a bug in Gitea 1.25)
- All settings are versioned in Git
- Better maintainability and reliability
- Configuration follows Gitea documentation recommendations

deployment/ansible/templates/gitea-app.ini.j2

@@ -1,12 +1,14 @@
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; Gitea Configuration File - Minimal Version
+;; Gitea Configuration File
 ;; Generated by Ansible - DO NOT EDIT MANUALLY
 ;; 
-;; IMPORTANT: This is a minimal configuration. Cache, Session, Queue, and other
-;; settings are controlled via GITEA__... environment variables in docker-compose.yml
-;; which override these settings on every container start.
+;; All Gitea configuration is now managed via app.ini instead of
+;; environment variables for better reliability and maintainability.
 ;; 
-;; Only essential values are included here to skip installation and enable basic functionality.
+;; Migration from environment variables to app.ini:
+;; - Cache now works correctly (environment variables had a bug in Gitea 1.25)
+;; - All settings are versioned in Git
+;; - Better documentation and maintainability
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 APP_NAME = Gitea: Git with a cup of tea
@@ -37,6 +39,43 @@ NAME = {{ postgres_db | default('gitea') }}
 USER = {{ postgres_user | default('gitea') }}
 PASSWD = {{ postgres_password | default('gitea_password') }}
 SSL_MODE = disable
+# Connection pool settings to prevent "Timeout before authentication" errors
+# These limit the number of concurrent connections and prevent connection pool exhaustion
+# - MAX_OPEN_CONNS: Maximum number of open connections to the database
+# - MAX_IDLE_CONNS: More warm connections to avoid constantly creating new sessions
+# - CONN_MAX_LIFETIME: 10 minutes; idle connections are not recycled too quickly
+# - CONN_MAX_IDLE_TIME: Clean up connections that are idle for too long
+MAX_OPEN_CONNS = 50
+MAX_IDLE_CONNS = 30
+CONN_MAX_LIFETIME = 600
+CONN_MAX_IDLE_TIME = 300
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Cache Configuration (Redis)
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+[cache]
+ENABLED = true
+ADAPTER = redis
+# HOST must be a Redis connection string (as per Gitea documentation)
+# Format: redis://:password@host:port/db?pool_size=100&idle_timeout=180s
+# Using same format as queue CONN_STR for consistency
+HOST = redis://:{{ redis_password }}@redis:6379/0?pool_size=100&idle_timeout=180s
+# Cache configuration now works correctly in app.ini
+# (Environment variables had a bug in Gitea 1.25 that connected to 127.0.0.1:6379 instead of redis:6379)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Session Configuration (Redis)
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+[session]
+PROVIDER = redis
+PROVIDER_CONFIG = network=tcp,addr=redis:6379,password={{ redis_password }},db=0,pool_size=100,idle_timeout=180
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Queue Configuration (Redis)
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+[queue]
+TYPE = redis
+CONN_STR = redis://:{{ redis_password }}@redis:6379/0
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Security Configuration
@@ -54,9 +93,4 @@ DISABLE_REGISTRATION = {{ disable_registration | default(true) | lower }}
 ;; Actions Configuration
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 [actions]
-ENABLED = true
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; Cache Configuration
-;; NOTE: Cache configuration is controlled via GITEA__cache__ environment variables
-;; in docker-compose.yml. Do NOT add [cache] section here, as it may cause conflicts.
+ENABLED = true