feat: add momentry_playground binary for development

- Add separate momentry_playground binary with distinct configuration
- Production (momentry): Port 3002, Redis prefix 'momentry:'
- Development (momentry_playground): Port 3003, Redis prefix 'momentry_dev:'
- Add SERVER_PORT and REDIS_KEY_PREFIX config via environment variables
- Replace all hardcoded Redis key prefixes with configurable values
- Create .env.development for playground environment settings
- Update .env with production defaults
- Add dotenv dependency for environment file loading

Configuration isolation allows running both binaries simultaneously
without port conflicts or Redis key collisions.

src/core/config.rs

@@ -0,0 +1,139 @@
+use once_cell::sync::Lazy;
+use std::env;
+
+pub static DATABASE_URL: Lazy<String> = Lazy::new(|| {
+    env::var("DATABASE_URL")
+        .unwrap_or_else(|_| "postgres://accusys@localhost:5432/momentry".to_string())
+});
+
+pub static MONGODB_URL: Lazy<String> = Lazy::new(|| {
+    env::var("MONGODB_URL").unwrap_or_else(|_| "mongodb://localhost:27017".to_string())
+});
+
+pub static REDIS_URL: Lazy<String> = Lazy::new(|| {
+    env::var("REDIS_URL").unwrap_or_else(|_| {
+        let password = env::var("REDIS_PASSWORD").unwrap_or_else(|_| "accusys".to_string());
+        // Format: redis://[:password]@host:port (use default user)
+        format!("redis://:{}@localhost:6379", password)
+    })
+});
+
+pub static REDIS_PASSWORD: Lazy<String> =
+    Lazy::new(|| env::var("REDIS_PASSWORD").unwrap_or_else(|_| "accusys".to_string()));
+
+pub static OUTPUT_DIR: Lazy<String> = Lazy::new(|| {
+    env::var("MOMENTRY_OUTPUT_DIR").unwrap_or_else(|_| "/Users/accusys/momentry/output".to_string())
+});
+
+pub static BACKUP_DIR: Lazy<String> = Lazy::new(|| {
+    env::var("MOMENTRY_BACKUP_DIR")
+        .unwrap_or_else(|_| "/Users/accusys/momentry/backup/momentry".to_string())
+});
+
+pub static PYTHON_PATH: Lazy<String> = Lazy::new(|| {
+    env::var("MOMENTRY_PYTHON_PATH").unwrap_or_else(|_| "/opt/homebrew/bin/python3.11".to_string())
+});
+
+pub static SCRIPTS_DIR: Lazy<String> = Lazy::new(|| {
+    env::var("MOMENTRY_SCRIPTS_DIR")
+        .unwrap_or_else(|_| "/Users/accusys/momentry_core_0.1/scripts".to_string())
+});
+
+pub static LOG_LEVEL: Lazy<String> = Lazy::new(|| {
+    env::var("RUST_LOG")
+        .or_else(|_| env::var("MOMENTRY_LOG_LEVEL"))
+        .unwrap_or_else(|_| "info".to_string())
+});
+
+pub static MEDIA_BASE_URL: Lazy<String> = Lazy::new(|| {
+    env::var("MOMENTRY_MEDIA_BASE_URL")
+        .unwrap_or_else(|_| "https://wp.momentry.ddns.net".to_string())
+});
+
+pub static SERVER_PORT: Lazy<u16> = Lazy::new(|| {
+    env::var("MOMENTRY_SERVER_PORT")
+        .unwrap_or_else(|_| "3002".to_string())
+        .parse()
+        .unwrap_or(3002)
+});
+
+pub static REDIS_KEY_PREFIX: Lazy<String> =
+    Lazy::new(|| env::var("MOMENTRY_REDIS_PREFIX").unwrap_or_else(|_| "momentry:".to_string()));
+
+pub mod processor {
+    use super::*;
+
+    pub static ASR_TIMEOUT_SECS: Lazy<u64> = Lazy::new(|| {
+        env::var("MOMENTRY_ASR_TIMEOUT")
+            .unwrap_or_else(|_| "3600".to_string())
+            .parse()
+            .unwrap_or(3600)
+    });
+
+    pub static CUT_TIMEOUT_SECS: Lazy<u64> = Lazy::new(|| {
+        env::var("MOMENTRY_CUT_TIMEOUT")
+            .unwrap_or_else(|_| "3600".to_string())
+            .parse()
+            .unwrap_or(3600)
+    });
+
+    pub static DEFAULT_TIMEOUT_SECS: Lazy<u64> = Lazy::new(|| {
+        env::var("MOMENTRY_DEFAULT_TIMEOUT")
+            .unwrap_or_else(|_| "7200".to_string())
+            .parse()
+            .unwrap_or(7200)
+    });
+}
+
+pub mod cache {
+    use super::*;
+
+    pub static MONGODB_CACHE_ENABLED: Lazy<bool> = Lazy::new(|| {
+        env::var("MONGODB_CACHE_ENABLED")
+            .unwrap_or_else(|_| "true".to_string())
+            .parse()
+            .unwrap_or(true)
+    });
+
+    pub static MONGODB_CACHE_TTL_VIDEOS: Lazy<u64> = Lazy::new(|| {
+        env::var("MONGODB_CACHE_TTL_VIDEOS")
+            .unwrap_or_else(|_| "300".to_string())
+            .parse()
+            .unwrap_or(300)
+    });
+
+    pub static MONGODB_CACHE_TTL_SEARCH: Lazy<u64> = Lazy::new(|| {
+        env::var("MONGODB_CACHE_TTL_SEARCH")
+            .unwrap_or_else(|_| "300".to_string())
+            .parse()
+            .unwrap_or(300)
+    });
+
+    pub static MONGODB_CACHE_TTL_HYBRID_SEARCH: Lazy<u64> = Lazy::new(|| {
+        env::var("MONGODB_CACHE_TTL_HYBRID_SEARCH")
+            .unwrap_or_else(|_| "600".to_string())
+            .parse()
+            .unwrap_or(600)
+    });
+
+    pub static MONGODB_CACHE_TTL_VIDEO_META: Lazy<u64> = Lazy::new(|| {
+        env::var("MONGODB_CACHE_TTL_VIDEO_META")
+            .unwrap_or_else(|_| "3600".to_string())
+            .parse()
+            .unwrap_or(3600)
+    });
+
+    pub static REDIS_CACHE_TTL_HEALTH: Lazy<u64> = Lazy::new(|| {
+        env::var("REDIS_CACHE_TTL_HEALTH")
+            .unwrap_or_else(|_| "30".to_string())
+            .parse()
+            .unwrap_or(30)
+    });
+
+    pub static REDIS_CACHE_TTL_VIDEO_META: Lazy<u64> = Lazy::new(|| {
+        env::var("REDIS_CACHE_TTL_VIDEO_META")
+            .unwrap_or_else(|_| "3600".to_string())
+            .parse()
+            .unwrap_or(3600)
+    });
+}