docs: add Code of Conduct and community guide for GitHub Discussions

Establishes Contributor Covenant 2.1 as the project Code of Conduct with
reporting to ashim.hq@gmail.com. Adds a community guide with the 5-category
Discussions layout, a pinned Welcome post draft, and seed post ideas.

docs/COMMUNITY_GUIDE.md

@@ -0,0 +1,110 @@
+# Community Guide — GitHub Discussions Setup
+
+This document contains the category structure, pinned Welcome post, and seed
+post ideas for the ashim GitHub Discussions.
+
+---
+
+## Discussion Categories
+
+Create these 5 categories in **Settings → Discussions → Categories** on GitHub.
+
+| Category | Format | Description |
+|----------|--------|-------------|
+| **General** | Open | Announcements, project updates, and casual conversation about ashim. Pinned Welcome post lives here. |
+| **Q&A** | Question / Answer | Ask for help with image processing, tool behavior, or unexpected results. Mark accepted answers so others can find solutions quickly. |
+| **Ideas** | Open | Suggest new tools, improvements to existing features, or workflow changes. Upvote ideas you want to see prioritized. |
+| **Show & Tell** | Open | Share your ashim setup — screenshots of pipelines, Docker Compose configs, automation scripts using the REST API, before/after results. |
+| **Self-Hosting Help** | Question / Answer | Docker, reverse proxy, storage, networking, multi-arch, and environment configuration. If your question is about getting ashim running rather than using its tools, post here. |
+
+### Why these categories
+
+- **Q&A vs Self-Hosting Help** — Separating "how do I use the resize tool" from
+  "how do I get ashim behind Caddy" keeps both channels useful. Self-hosters
+  and image-tool users are often different people with different expertise.
+- **Show & Tell** — Pipeline sharing/export isn't built into the app yet, so
+  this category is the place to describe your workflows with screenshots and
+  step lists. When export lands, this becomes the natural home for shared
+  pipeline files.
+- **Ideas over Issues** — Feature requests in Discussions get community
+  upvotes and discussion before becoming actionable Issues.
+
+---
+
+## Pinned Welcome Post
+
+> **Title:** Welcome to ashim Discussions
+>
+> **Category:** General
+>
+> ---
+>
+> Thanks for joining the ashim community. This is the place to ask questions,
+> suggest features, and share what you're building with ashim.
+>
+> **Where to post:**
+>
+> | I want to... | Post in |
+> |---|---|
+> | Ask how to use a tool or fix unexpected output | [Q&A] |
+> | Get help with Docker, reverse proxies, or deployment | [Self-Hosting Help] |
+> | Suggest a new feature or improvement | [Ideas] |
+> | Show off my setup, pipeline, or results | [Show & Tell] |
+> | Report a bug | [GitHub Issues](https://github.com/ashim-hq/ashim/issues/new/choose) |
+> | Report a security vulnerability | [Security Advisories](https://github.com/ashim-hq/ashim/security/advisories/new) |
+>
+> **A few ground rules:**
+>
+> - Search before posting — your question may already have an answer.
+> - In Q&A and Self-Hosting Help, mark the reply that solved your problem so
+>   others can find it.
+> - Keep it constructive. We follow the
+>   [Code of Conduct](https://github.com/ashim-hq/ashim/blob/main/CODE_OF_CONDUCT.md).
+>
+> If you're new to ashim, the
+> [documentation](https://github.com/ashim-hq/ashim#readme) is the best
+> starting point.
+
+---
+
+## Seed Posts
+
+Two posts you can publish yourself to get early activity in the community.
+
+### Seed Post 1 — Self-Hosting Help
+
+> **Title:** What's your ashim deployment setup?
+>
+> **Category:** Self-Hosting Help
+>
+> I'm curious how everyone is running ashim. A few things I'd love to hear
+> about:
+>
+> - Are you running it on a NAS, a VPS, or a home server?
+> - What reverse proxy are you using (Traefik, Caddy, nginx)?
+> - Have you enabled the AI features, and if so, how much RAM/VRAM does your
+>   setup have?
+>
+> I'll go first — I run ashim on [describe your own setup here] with
+> [reverse proxy] in front. The AI sidecar uses about [X] GB of RAM on my
+> machine.
+
+### Seed Post 2 — Show & Tell
+
+> **Title:** Share your favorite pipeline
+>
+> **Category:** Show & Tell
+>
+> Pipelines let you chain multiple image tools together and run them in one
+> pass. I'd love to see what workflows people are building.
+>
+> Since there's no export button yet, just describe your steps or post a
+> screenshot of your pipeline builder. Here's one of mine:
+>
+> **"Blog image prep"** — 4 steps:
+> 1. Resize (max width 1200px)
+> 2. Convert to WebP (quality 85)
+> 3. Strip metadata
+> 4. Compress (target 200 KB)
+>
+> What does yours look like?