feat(query-optimization): implement GraphQL query optimization and enhance regression suite

- **Optimization**: Implemented automatic Zabbix parameter optimization by analyzing GraphQL selection sets.

- **ZabbixRequest**: Added optimizeZabbixParams with support for skippable parameters and implied field dependencies (e.g., state -> items).

- **Resolvers**: Updated allHosts, allDevices, allHostGroups, and templates to pass requested fields to data sources.

- **Data Sources**: Optimized ZabbixQueryHostsGenericRequest and ZabbixQueryTemplatesRequest to skip unnecessary Zabbix API calls.

- **Regression Tests**: Enhanced RegressionTestExecutor with new tests for optimization (REG-OPT, REG-OPT-NEG), state retrieval (REG-STATE), dependent items (REG-DEP), and empty results (REG-EMPTY).

- **Documentation**: Created query_optimization.md How-To guide and updated roadmap.md, README.md, and tests.md.

- **Bug Fixes**: Fixed deviceType tag assignment during host import and corrected ZabbixCreateHostRequest to support tags.

docs/howtos/query_optimization.md

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+# ⚡ Query Optimization
+
+This document describes how the Zabbix GraphQL API optimizes queries to reduce data fetching from Zabbix, improving performance and reducing network load.
+
+## 🚀 Overview
+
+The optimization works by analyzing the requested GraphQL fields and only fetching the necessary data from the Zabbix API. This is achieved through:
+- **Output Reduction**: Dynamically setting the `output` parameter in Zabbix requests.
+- **Parameter Skipping**: Automatically removing optional Zabbix parameters (like `selectTags` or `selectItems`) if the corresponding GraphQL fields are not requested.
+
+## 🏗️ Implementation Details
+
+### 1. `ZabbixRequest` Enhancement
+The base `ZabbixRequest` class handles the core optimization logic:
+- `optimizeZabbixParams(params, output)`: This method modifies the Zabbix parameters. It filters the `output` array to match the requested fields and removes "skippable" parameters based on rules.
+- `skippableZabbixParams`: A map that defines dependencies between Zabbix parameters and GraphQL fields.
+    - *Example*: `this.skippableZabbixParams.set("selectTags", "tags")` means `selectTags` will be removed if `tags` is not in the requested output.
+
+### 2. Parameter Mapping
+The `GraphqlParamsToNeededZabbixOutput` class provides static methods to map GraphQL query arguments and the selection set (`GraphQLResolveInfo`) to a list of needed Zabbix fields.
+
+### 3. Resolver Integration
+Resolvers use the mapper to determine the required output and pass it to the datasource:
+```typescript
+const output = GraphqlParamsToNeededZabbixOutput.mapAllHosts(args, info);
+return await new ZabbixQueryHostsRequestWithItemsAndInventory(...)
+    .executeRequestThrowError(dataSources.zabbixAPI, new ParsedArgs(args), output);
+```
+
+### 4. Indirect Dependencies
+Some GraphQL fields are not directly returned by Zabbix but are computed from other data. The optimization logic ensures these dependencies are handled:
+- **`state`**: Requesting the `state` field on a `Device` requires Zabbix `items`. The mapper automatically adds `items` to the requested output if `state` is present.
+
+## 🛠️ Configuration
+Optimization rules are defined in the constructor of specialized `ZabbixRequest` classes.
+
+### 📋 Supported Optimizations
+- **Hosts & Devices**:
+    - `selectParentTemplates` skipped if `parentTemplates` not requested.
+    - `selectTags` and `selectInheritedTags` skipped if `tags` not requested.
+    - `selectHostGroups` skipped if `hostgroups` not requested.
+    - `selectItems` skipped if `items` (or `state`) not requested.
+    - `selectInventory` skipped if `inventory` not requested.
+- **Templates**:
+    - `selectItems` skipped if `items` not requested.
+
+## ✅ Verification
+You can verify that optimization is working by:
+1. Enabling `debug` log level (`LOG_LEVEL=debug`).
+2. Observing the Zabbix request bodies in the logs.
+3. Checking that the `output` array is minimized and `select*` parameters are omitted when not needed.