Simplify contributor guide: file an issue, we implement it

Lower the understanding barrier for contributors:
- Lead with "no programming required" and a 3-step flow
- Add community calls section (coming soon via Zulip)
- Update reduction graph legend for new model categories
- Update design.md module table for new category names

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: GiggleLiu

README.md

@@ -63,31 +63,22 @@ See the [MCP documentation](https://codingthrust.github.io/problem-reductions/mc
 
 ## Contributing
 
-### Authorship Recognition
+**No programming experience required.** You contribute domain knowledge; we handle the implementation.
 
-**Contribute 10 non-trivial reduction rules and you will be automatically added to the author list of the paper.** AI tools handle the implementation — contributors focus on designing correct reductions and test cases.
+1. **File an issue** — use the [Problem](https://github.com/CodingThrust/problem-reductions/issues/new?template=problem.md) or [Rule](https://github.com/CodingThrust/problem-reductions/issues/new?template=rule.md) template. Describe the problem or reduction you have in mind — the template guides you through the details.
+2. **We implement it** — for reasonable requests, maintainers tag the issue `implement` and AI agents generate a tested pull request.
+3. **You review it** — you'll be mentioned on the PR to provide feedback. We present the implementation and iterate until you're satisfied.
 
-### How to Contribute
+**Community calls** (coming soon via [Zulip](https://zulip.com/)): all issue contributors will be invited. Maintainers walk through recent implementations so you can ask questions and give feedback in real time.
 
-1. **Open an issue** using the [Problem](https://github.com/CodingThrust/problem-reductions/issues/new?template=problem.md) or [Rule](https://github.com/CodingThrust/problem-reductions/issues/new?template=rule.md) template. Fill in all sections — the templates guide you through the required information (definition, algorithm, size overhead, example instance, etc.).
+**Authorship:** contribute 10 non-trivial reduction rules and you'll be added to the author list of the [paper](https://codingthrust.github.io/problem-reductions/reductions.pdf).
 
-   **Hint:** If you use Claude Code / OpenCode / Codex (assume `gh` CLI tool and `superpowers` plugin are installed), you can just type:
-   ```
-   File an issue on CodingThrust/problem-reductions, using the "Model" issue template, about the Closest Vector Problem. Brainstorm with me.
-   ```
-   ```
-   File an issue on CodingThrust/problem-reductions, using the "Rule" issue template, about reduction from Closest Vector Problem to QUBO. Brainstorm with me.
-   ```
-   Then AI agents will guide you to fill in the issue template.
+> **Tip:** If you use Claude Code / OpenCode / Codex, you can file issues interactively:
+> ```
+> File an issue on CodingThrust/problem-reductions, using the "Model" issue template, about the Closest Vector Problem. Brainstorm with me.
+> ```
 
-2. Our AI agents will pick up the issue and generate a plan to implement the reduction rule.
-3. You will be mentioned in the pull request, provide feedback to the AI agents. If you are satisfied with the plan, you can merge the PR.
-
-Optionally, if you prefer to **implement yourself**, I will recommend you to use the [superpowers:brainstorming](https://github.com/obra/superpowers) skill to help you write a detailed plan. Create a PR and let maintainers help review and merge the PR.
-
-### Developer Commands
-
-Run `make help` to see all available targets. See [CLAUDE.md](https://codingthrust.github.io/problem-reductions/claude.html) for the full command list and architecture details.
+If you prefer to **implement yourself**, see the [Design](https://codingthrust.github.io/problem-reductions/design.html) guide. Run `make help` to see available developer commands.
 
 ## Acknowledgments
 

docs/src/design.md

@@ -17,7 +17,7 @@ This guide covers the library internals for contributors.
 
 | Module | Purpose |
 |--------|---------|
-| [`src/models/`](#problem-model) | Problem type implementations (SAT, Graph, Set, Optimization) |
+| [`src/models/`](#problem-model) | Problem implementations by input structure: `graph/`, `formula/`, `set/`, `algebraic/`, `misc/` |
 | [`src/rules/`](#reduction-rules) | Reduction rules with `ReduceTo` implementations |
 | [`src/registry/`](#reduction-graph) | Reduction graph metadata (collected via `inventory`) |
 | [`src/solvers/`](#solvers) | BruteForce and ILP solvers |

docs/src/introduction.md

@@ -14,10 +14,10 @@
 <div id="cy-controls">
   <div id="legend">
     <span class="swatch" style="background:#c8f0c8;"></span>Graph
+    <span class="swatch" style="background:#c8c8f0;"></span>Formula
     <span class="swatch" style="background:#f0c8c8;"></span>Set
-    <span class="swatch" style="background:#f0f0a0;"></span>Optimization
-    <span class="swatch" style="background:#c8c8f0;"></span>Satisfiability
-    <span class="swatch" style="background:#f0c8e0;"></span>Specialized
+    <span class="swatch" style="background:#f0f0a0;"></span>Algebraic
+    <span class="swatch" style="background:#f0c8e0;"></span>Misc
     <span style="display:inline-block;width:20px;height:0;border-top:2px dashed #bbb;margin-left:10px;margin-right:3px;vertical-align:middle;"></span>Variant Cast
   </div>
   <div>
@@ -62,14 +62,21 @@ This library is the foundation of that effort: an open-source, extensible reduct
 
 ## Call for Contributions
 
-> **Everyone can contribute — no programming experience required.** If you know a computational problem or a reduction rule, just describe it in a GitHub issue. AI will generate a tested pull request for you to review.
->
-> **Contribute 10 non-trivial reduction rules and you will be automatically added to the author list of the [paper](https://codingthrust.github.io/problem-reductions/reductions.pdf).**
+> **No programming experience required.** You contribute domain knowledge — we handle the implementation.
 
-1. **Open an issue** using the [Problem](https://github.com/CodingThrust/problem-reductions/issues/new?template=problem.md) or [Rule](https://github.com/CodingThrust/problem-reductions/issues/new?template=rule.md) template
-2. **Fill in all sections** — definition, algorithm, size overhead, example instance
-3. **Review AI-generated code** — AI generates code and you can comment on the pull request
-4. **Merge** — ask maintainers' assistance to merge once you are satisfied
+### How it works
+
+1. **File an issue** — use the [Problem](https://github.com/CodingThrust/problem-reductions/issues/new?template=problem.md) or [Rule](https://github.com/CodingThrust/problem-reductions/issues/new?template=rule.md) template. Describe the problem or reduction you have in mind; the template guides you through the details.
+2. **We implement it** — for reasonable requests, maintainers tag the issue `implement` and AI agents generate a tested pull request.
+3. **You review it** — you'll be mentioned on the PR to provide feedback. We iterate until you're satisfied.
+
+### Community calls
+
+Coming soon via [Zulip](https://zulip.com/). All issue contributors will be invited. Maintainers walk through recent implementations so you can ask questions and give feedback in real time.
+
+### Authorship
+
+Contribute 10 non-trivial reduction rules and you'll be added to the author list of the [paper](https://codingthrust.github.io/problem-reductions/reductions.pdf).
 
 For manual implementation, see the [Design](./design.md#contributing) guide.