Add professional project structure and documentation

New files:
- LICENSE (MIT) - Required legal file
- CHANGELOG.md - Version history following Keep a Changelog
- CONTRIBUTING.md - Contributor guidelines
- CODE_OF_CONDUCT.md - Community standards
- .github/ISSUE_TEMPLATE/ - Bug report and feature request forms
- .github/PULL_REQUEST_TEMPLATE.md - PR checklist
- src/stegasoo/py.typed - PEP 561 type hint marker
- examples/ - Usage examples (basic, file embedding, channel keys)

Updated:
- README.md - Added CI status badges

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,98 @@
+name: Bug Report
+description: Report a bug or unexpected behavior
+title: "[Bug]: "
+labels: ["bug", "triage"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for taking the time to report a bug! Please fill out the form below.
+
+  - type: textarea
+    id: description
+    attributes:
+      label: Bug Description
+      description: A clear and concise description of what the bug is.
+      placeholder: Describe the bug...
+    validations:
+      required: true
+
+  - type: textarea
+    id: reproduction
+    attributes:
+      label: Steps to Reproduce
+      description: Steps to reproduce the behavior.
+      placeholder: |
+        1. Run command '...'
+        2. Upload image '...'
+        3. See error
+    validations:
+      required: true
+
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected Behavior
+      description: What did you expect to happen?
+    validations:
+      required: true
+
+  - type: textarea
+    id: actual
+    attributes:
+      label: Actual Behavior
+      description: What actually happened?
+    validations:
+      required: true
+
+  - type: dropdown
+    id: interface
+    attributes:
+      label: Interface
+      description: Which interface are you using?
+      options:
+        - CLI
+        - Web UI
+        - REST API
+        - Python Library
+    validations:
+      required: true
+
+  - type: input
+    id: version
+    attributes:
+      label: Stegasoo Version
+      description: Run `stegasoo --version` or check the web UI footer
+      placeholder: "4.0.1"
+    validations:
+      required: true
+
+  - type: input
+    id: python-version
+    attributes:
+      label: Python Version
+      description: Run `python --version`
+      placeholder: "3.11.0"
+    validations:
+      required: true
+
+  - type: input
+    id: os
+    attributes:
+      label: Operating System
+      placeholder: "Ubuntu 22.04 / Windows 11 / macOS 14"
+    validations:
+      required: true
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Error Logs
+      description: Paste any relevant error messages or tracebacks.
+      render: shell
+
+  - type: textarea
+    id: additional
+    attributes:
+      label: Additional Context
+      description: Add any other context, screenshots, or files here.