fix: [CN-70] require JSON processors in log handlers

[vpakhuchyi]

Pull request

Link to the related ticket

https://censor.atlassian.net/browse/CN-70

Description of changes

• add Processor.OutputFormat so integrations can inspect the active encoder
• guard zerolog, zap, and slog handlers against text-mode processors
• document the JSON requirement and cover panic paths with regression tests

Checklist

Please ensure that your pull request complies with the following requirements:

• The changes have been tested locally (if applicable).
• The documentation has been updated (if applicable).

[Copilot]

Pull Request Overview

This pull request adds validation to ensure log handlers only accept JSON-mode processors, preventing runtime issues when text-mode processors are used with structured logging frameworks.

• Introduces OutputFormat() method on Processor to expose the configured output format
• Adds runtime checks in zerolog, zap, and slog handlers that panic if a text-mode processor is provided
• Includes comprehensive test coverage for the new validation logic

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
processor.go	Adds OutputFormat() method to expose processor configuration; refactors string literal to use constant
processor_test.go	Adds test coverage for OutputFormat() method including nil processor panic case
handlers/zerolog/handler.go	Adds validation to panic if text-mode processor is used; updates function signature to use any instead of interface{}
handlers/zerolog/handler_test.go	Adds regression test for text-mode processor panic scenario; fixes indentation in existing test
handlers/zerolog/doc.go	Documents JSON requirement for processors
handlers/zap/handler.go	Adds validation to panic if text-mode processor is used
handlers/zap/handler_test.go	Adds regression test for text-mode processor panic scenario
handlers/zap/doc.go	Documents JSON requirement for processors
handlers/slog/handler.go	Adds validation to panic if text-mode processor is used
handlers/slog/handler_test.go	Adds regression test for text-mode processor panic scenario
handlers/slog/doc.go	Documents JSON requirement; updates example email address for consistency

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