refactor(config): Standardize env var access and config getters

This commit focuses on standardizing configuration and API key access patterns across key modules as part of subtask 61.34.

Key changes include:

- Refactored `ai-services.js` to remove global AI clients and use `resolveEnvVariable` for API key checks. Client instantiation now relies on `getAnthropicClient`/`getPerplexityClient` accepting a session object.

- Refactored `task-manager.js` (`analyzeTaskComplexity` function) to use the unified `generateTextService` from `ai-services-unified.js`, removing direct AI client calls.

- Replaced direct `process.env` access for model parameters and other configurations (`PERPLEXITY_MODEL`, `CONFIG.*`) in `task-manager.js` with calls to the appropriate getters from `config-manager.js` (e.g., `getResearchModelId(session)`, `getMainMaxTokens(session)`).

- Ensured `utils.js` (`resolveEnvVariable`) correctly handles potentially undefined session objects.

- Updated function signatures where necessary to propagate the `session` object for correct context-aware configuration/key retrieval.

This moves towards the goal of using `ai-client-factory.js` and `ai-services-unified.js` as the standard pattern for AI interactions and centralizing configuration management through `config-manager.js`.

scripts/modules/task-manager/find-next-task.js

@@ -0,0 +1,57 @@
+/**
+ * Find the next pending task based on dependencies
+ * @param {Object[]} tasks - The array of tasks
+ * @returns {Object|null} The next task to work on or null if no eligible tasks
+ */
+function findNextTask(tasks) {
+	// Get all completed task IDs
+	const completedTaskIds = new Set(
+		tasks
+			.filter((t) => t.status === 'done' || t.status === 'completed')
+			.map((t) => t.id)
+	);
+
+	// Filter for pending tasks whose dependencies are all satisfied
+	const eligibleTasks = tasks.filter(
+		(task) =>
+			(task.status === 'pending' || task.status === 'in-progress') &&
+			task.dependencies && // Make sure dependencies array exists
+			task.dependencies.every((depId) => completedTaskIds.has(depId))
+	);
+
+	if (eligibleTasks.length === 0) {
+		return null;
+	}
+
+	// Sort eligible tasks by:
+	// 1. Priority (high > medium > low)
+	// 2. Dependencies count (fewer dependencies first)
+	// 3. ID (lower ID first)
+	const priorityValues = { high: 3, medium: 2, low: 1 };
+
+	const nextTask = eligibleTasks.sort((a, b) => {
+		// Sort by priority first
+		const priorityA = priorityValues[a.priority || 'medium'] || 2;
+		const priorityB = priorityValues[b.priority || 'medium'] || 2;
+
+		if (priorityB !== priorityA) {
+			return priorityB - priorityA; // Higher priority first
+		}
+
+		// If priority is the same, sort by dependency count
+		if (
+			a.dependencies &&
+			b.dependencies &&
+			a.dependencies.length !== b.dependencies.length
+		) {
+			return a.dependencies.length - b.dependencies.length; // Fewer dependencies first
+		}
+
+		// If dependency count is the same, sort by ID
+		return a.id - b.id; // Lower ID first
+	})[0]; // Return the first (highest priority) task
+
+	return nextTask;
+}
+
+export default findNextTask;