LLM cost estimation (#223)

* Password reset back button also after confirmation

Signed-off-by: Juan José Mata <juanjo.mata@gmail.com>

* Implement a filter for category (#215)

- Also implement an is empty/is null condition.

* Implement an LLM cost estimation page

Track costs across all the cost categories: auto categorization, auto merchant detection and chat.
Show warning with estimated cost when running a rule that contains AI.

* Update pricing

* Add google pricing

and fix inferred model everywhere.

* Update app/models/llm_usage.rb

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: soky srm <sokysrm@gmail.com>

* FIX address review

* Linter

* Address review

- Lowered log level
- extracted the duplicated record_usage method into a shared concern

* Update app/controllers/settings/llm_usages_controller.rb

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: soky srm <sokysrm@gmail.com>

* Moved attr_reader out of private

---------

Signed-off-by: Juan José Mata <juanjo.mata@gmail.com>
Signed-off-by: soky srm <sokysrm@gmail.com>
Co-authored-by: Juan José Mata <juanjo.mata@gmail.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

app/models/provider/openai/concerns/usage_recorder.rb

@@ -0,0 +1,47 @@
+module Provider::Openai::Concerns::UsageRecorder
+  extend ActiveSupport::Concern
+
+  private
+
+    # Records LLM usage for a family
+    # Handles both old (prompt_tokens/completion_tokens) and new (input_tokens/output_tokens) API formats
+    # Automatically infers provider from model name
+    # Returns nil if pricing is unavailable (e.g., custom/self-hosted models)
+    def record_usage(model_name, usage_data, operation:, metadata: {})
+      return unless family && usage_data
+
+      # Handle both old and new OpenAI API response formats
+      # Old format: prompt_tokens, completion_tokens, total_tokens
+      # New format: input_tokens, output_tokens, total_tokens
+      prompt_tokens = usage_data["prompt_tokens"] || usage_data["input_tokens"] || 0
+      completion_tokens = usage_data["completion_tokens"] || usage_data["output_tokens"] || 0
+      total_tokens = usage_data["total_tokens"] || 0
+
+      estimated_cost = LlmUsage.calculate_cost(
+        model: model_name,
+        prompt_tokens: prompt_tokens,
+        completion_tokens: completion_tokens
+      )
+
+      # Log when we can't estimate the cost (e.g., custom/self-hosted models)
+      if estimated_cost.nil?
+        Rails.logger.info("Recording LLM usage without cost estimate for unknown model: #{model_name} (custom provider: #{custom_provider})")
+      end
+
+      inferred_provider = LlmUsage.infer_provider(model_name)
+      family.llm_usages.create!(
+        provider: inferred_provider,
+        model: model_name,
+        operation: operation,
+        prompt_tokens: prompt_tokens,
+        completion_tokens: completion_tokens,
+        total_tokens: total_tokens,
+        estimated_cost: estimated_cost,
+        metadata: metadata
+      )
+
+      Rails.logger.info("LLM usage recorded - Operation: #{operation}, Cost: #{estimated_cost.inspect}")
+    rescue => e
+      Rails.logger.error("Failed to record LLM usage: #{e.message}")
+    end
+end