docs: add community governance and contribution guidelines

- Add CONTRIBUTING.md with TDD requirements, PR workflow, and AI usage
  policy
- Add CODE_OF_CONDUCT.md based on Contributor Covenant
- Add SECURITY.md with vulnerability reporting scope and process
- Add AGENTS.md with AI usage policy for human contributors and AI
  agents
- Add CLAUDE.md to require reading AGENTS.md before any work
- Add Gitea issue templates for bug reports and feature requests
- Add pull request template with TDD and code quality checklist

.gitea/ISSUE_TEMPLATE/HARDWARE-COMPATIBILITY.yml

@@ -0,0 +1,73 @@
+name: Hardware Compatibility Report
+description: Report compatibility issues with a specific Modbus relay device
+title: "[Hardware]: "
+labels: ["hardware", "compatibility"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Use this template to report issues specific to a Modbus relay device that STA
+        fails to communicate with or control correctly.
+  - type: textarea
+    id: device-info
+    attributes:
+      label: Device information
+      description: Manufacturer, model, and firmware version of the relay device
+      placeholder: |
+        Manufacturer: ...
+        Model: ...
+        Firmware: ...
+    validations:
+      required: true
+  - type: textarea
+    id: modbus-config
+    attributes:
+      label: Modbus configuration
+      description: The Modbus settings you are using (from your base.yaml or environment variables)
+      placeholder: |
+        host: 192.168.x.x
+        port: 502
+        slave_id: x
+        timeout_secs: x
+    validations:
+      required: true
+  - type: textarea
+    id: expected-behaviour
+    attributes:
+      label: Expected behaviour
+      description: What should STA be able to do with this device?
+      placeholder: "STA should be able to read and toggle all 8 relays"
+    validations:
+      required: true
+  - type: textarea
+    id: actual-behaviour
+    attributes:
+      label: Actual behaviour
+      description: What does STA actually do?
+      placeholder: "STA returns a Modbus exception or times out when writing a coil"
+    validations:
+      required: true
+  - type: textarea
+    id: logs
+    attributes:
+      label: Relevant log output
+      description: Please paste any relevant STA log output. This will be formatted as code automatically.
+      render: text
+    validations:
+      required: true
+  - type: dropdown
+    id: os-platform
+    attributes:
+      label: Operating system and platform
+      description: On which OS and hardware are you running the STA backend?
+      options:
+        - Linux (ARM / Raspberry Pi)
+        - Linux (x86_64)
+        - Other (please specify)
+    validations:
+      required: true
+  - type: textarea
+    id: additional-info
+    attributes:
+      label: Additional information
+      description: Any other context that may help, such as Modbus traffic captures, wiring details, or links to the device datasheet