Add GitHub issue and discussion templates

.github/CODEOWNERS

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+* @aether-framework/maintainers
+
+/.github/workflows/ @aether-framework/maintainers

.github/DISCUSSION_TEMPLATE/ideas.yml

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+title: "Idea / RFC"
+labels: ["enhancement", "discussion"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Use this to propose new features or API changes before opening a PR.
+        The more concrete the use-case, the better.
+
+  - type: textarea
+    id: motivation
+    attributes:
+      label: Motivation / Problem
+      placeholder: What problem does this solve?
+    validations:
+      required: true
+
+  - type: textarea
+    id: proposal
+    attributes:
+      label: Proposal
+      placeholder: Describe the proposed behavior and how users would use it.
+    validations:
+      required: true
+
+  - type: textarea
+    id: api
+    attributes:
+      label: API / Design Sketch (optional)
+      description: If you have a rough idea of the public API, put it here.
+      render: java
+    validations:
+      required: false
+
+  - type: textarea
+    id: breaking
+    attributes:
+      label: Breaking Changes / Migration
+      description: Would this be breaking? If yes, what would migration look like?
+    validations:
+      required: false
+
+  - type: dropdown
+    id: priority
+    attributes:
+      label: Priority (estimate)
+      options:
+        - low
+        - medium
+        - high
+    validations:
+      required: true

.github/DISCUSSION_TEMPLATE/q-a.yml

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+title: "Q&A / Help"
+labels: ["question"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Use this for usage questions and help requests.
+        For reproducible bugs, please open an Issue instead.
+
+  - type: input
+    id: version
+    attributes:
+      label: Version
+      description: Which version are you using?
+      placeholder: e.g. 0.5.0 (or main @ <commit>)
+    validations:
+      required: false
+
+  - type: dropdown
+    id: module
+    attributes:
+      label: Module
+      options:
+        - api
+        - core
+        - codec
+        - testkit
+        - cli
+        - schema-tools
+        - spring-boot-starter
+        - other / unknown
+    validations:
+      required: false
+
+  - type: textarea
+    id: goal
+    attributes:
+      label: Goal
+      description: What are you trying to accomplish?
+      placeholder: Be specific about the desired outcome.
+    validations:
+      required: true
+
+  - type: textarea
+    id: what_tried
+    attributes:
+      label: What did you try?
+      description: Include minimal code/config and what happened.
+      render: java
+    validations:
+      required: false
+
+  - type: textarea
+    id: context
+    attributes:
+      label: Context
+      description: Anything else that helps (stacktraces, links, constraints).
+    validations:
+      required: false

.github/DISCUSSION_TEMPLATE/show-and-tell.yml

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+title: "Show & Tell"
+labels: ["community"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Show what you built with this project!
+        Share links, screenshots, benchmarks, or lessons learned.
+
+  - type: input
+    id: project
+    attributes:
+      label: Project name
+      placeholder: e.g. MyGameSaveMigrator
+    validations:
+      required: true
+
+  - type: input
+    id: link
+    attributes:
+      label: Link (optional)
+      placeholder: Repository / website / blog post
+    validations:
+      required: false
+
+  - type: textarea
+    id: summary
+    attributes:
+      label: What did you build?
+      placeholder: Describe the project and how this library is used.
+    validations:
+      required: true
+
+  - type: textarea
+    id: learnings
+    attributes:
+      label: Learnings / Feedback
+      description: What worked well? What should be improved?
+    validations:
+      required: false

.github/ISSUE_TEMPLATE/bug_report.yml

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+name: 🐞 Bug Report
+description: Report a reproducible bug or unexpected behavior
+title: "[Bug]: "
+labels: ["bug", "needs-triage"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for the report! Please provide enough details so we can reproduce and fix the issue quickly.
+
+  - type: input
+    id: affected_version
+    attributes:
+      label: Affected Version
+      description: Which version(s) are affected?
+      placeholder: e.g. 0.5.0 (or main @ <commit>)
+    validations:
+      required: true
+
+  - type: dropdown
+    id: affected_module
+    attributes:
+      label: Affected Module
+      description: Which module is affected?
+      options:
+        - api
+        - core
+        - codec
+        - testkit
+        - cli
+        - schema-tools
+        - spring-boot-starter
+        - other / unknown
+    validations:
+      required: true
+
+  - type: textarea
+    id: summary
+    attributes:
+      label: Summary
+      description: Short summary of what is wrong.
+      placeholder: One or two sentences.
+    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 happened instead?
+    validations:
+      required: true
+
+  - type: textarea
+    id: repro_steps
+    attributes:
+      label: Steps to Reproduce
+      description: Provide a minimal, complete, reproducible set of steps.
+      placeholder: |
+        1. ...
+        2. ...
+        3. ...
+    validations:
+      required: true
+
+  - type: textarea
+    id: minimal_example
+    attributes:
+      label: Minimal Reproducible Example (code/config)
+      description: If possible, paste a small snippet that reproduces the issue.
+      render: java
+    validations:
+      required: false
+
+  - type: textarea
+    id: stacktrace
+    attributes:
+      label: Logs / Stacktrace
+      description: Paste relevant logs or the full stacktrace.
+      render: shell
+    validations:
+      required: false
+
+  - type: dropdown
+    id: regression
+    attributes:
+      label: Regression?
+      description: Did this work in a previous version?
+      options:
+        - "unknown"
+        - "yes"
+        - "no"
+    validations:
+      required: true
+
+  - type: input
+    id: last_working_version
+    attributes:
+      label: Last Known Working Version (if regression)
+      placeholder: e.g. 0.4.0
+    validations:
+      required: false
+
+  - type: input
+    id: environment
+    attributes:
+      label: Environment
+      description: Java version, OS, build tool, etc.
+      placeholder: e.g. Java 21, Maven 3.9.x, Windows 11 / Ubuntu 24.04
+    validations:
+      required: false
+
+  - type: checkboxes
+    id: checklist
+    attributes:
+      label: Checklist
+      options:
+        - label: I searched existing issues to avoid duplicates.
+          required: true
+        - label: I can reproduce this reliably.
+          required: false
+        - label: I included a minimal example or clear repro steps.
+          required: false

.github/ISSUE_TEMPLATE/config.yml

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+blank_issues_enabled: true
+contact_links:
+  - name: 🔒 Security Policy
+    url: https://github.com/aether-framework/aether-datafixers/security/policy
+    about: Please report serious vulnerabilities via the security policy / advisories.
+  - name: 📖 Documentation
+    url: https://github.com/aether-framework/aether-datafixers
+    about: Check the README and docs first.

.github/ISSUE_TEMPLATE/documentation.yml

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+name: 📚 Documentation
+description: Report missing, unclear, or incorrect documentation
+title: "[Docs]: "
+labels: ["documentation"]
+body:
+  - type: input
+    id: location
+    attributes:
+      label: Location
+      description: Where is the docs issue? (URL, file path, section)
+      placeholder: e.g. docs/codec.md#json or README.md#usage
+    validations:
+      required: true
+
+  - type: dropdown
+    id: type
+    attributes:
+      label: Type
+      options:
+        - typo / wording
+        - unclear explanation
+        - missing section
+        - incorrect/outdated information
+        - broken link
+        - example does not work
+    validations:
+      required: true
+
+  - type: textarea
+    id: current
+    attributes:
+      label: Current Content / Problem
+      description: What exactly is wrong right now?
+      placeholder: Paste the relevant snippet or describe the issue precisely.
+    validations:
+      required: true
+
+  - type: textarea
+    id: expected
+    attributes:
+      label: Suggested Change
+      description: What should it say/do instead?
+      placeholder: Proposed wording, fixed link, corrected example, etc.
+    validations:
+      required: false
+
+  - type: textarea
+    id: context
+    attributes:
+      label: Context (optional)
+      description: Why is it confusing? Who is the target audience?
+    validations:
+      required: false