docs: replace "hobby project" with "solo-maintained", add playground link

Removes "hobby project" framing from README, ROADMAP, SECURITY, and
CONTRIBUTING — the phrase signals low reliability expectations to readers,
not just time allocation. "Solo-maintained" is equally honest and conveys
the right durability posture.

Adds playground link to README intro for zero-friction evaluation.

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

Author: adityamukho

.github/SECURITY.md

@@ -28,7 +28,7 @@ Include as much of the following as possible:
 
 ## Response Timeline
 
-This is a solo hobby project. I will make a best-effort response:
+This is a solo-maintained project. I will make a best-effort response:
 
 - **Acknowledgement**: within 7 days
 - **Assessment**: within 14 days

CONTRIBUTING.md

@@ -1,6 +1,6 @@
 # Contributing to Minigraf
 
-Thank you for your interest in contributing. Minigraf is a hobby project with a long-term vision — quality and correctness matter more than pace. Please read this document before opening an issue or pull request.
+Thank you for your interest in contributing. Minigraf is a solo-maintained project with a long-term vision — quality and correctness matter more than pace. Please read this document before opening an issue or pull request.
 
 ## Before You Contribute
 

README.md

@@ -13,6 +13,8 @@
 
 A tiny, self-contained graph database with **Datalog queries** and **bi-temporal time travel**. Think SQLite, but for connected data with full history.
 
+**[Try it in your browser — no install needed →](https://minigraf-playground.vercel.app/)**
+
 ## Vision
 
 Minigraf is a **single-file embedded graph database** that lets you:
@@ -215,7 +217,7 @@ File-backed databases enforce a maximum fact size of **4 080 serialised bytes**
 
 ## Contributing
 
-This is a hobby project with a long-term vision. Read [PHILOSOPHY.md](PHILOSOPHY.md) and [ROADMAP.md](ROADMAP.md) before proposing features.
+This is a solo-maintained project with a long-term vision. Read [PHILOSOPHY.md](PHILOSOPHY.md) and [ROADMAP.md](ROADMAP.md) before proposing features.
 
 See [CONTRIBUTING.md](CONTRIBUTING.md) for development setup, code standards, and the PR process.
 

ROADMAP.md

@@ -1687,7 +1687,7 @@ When evaluating features, ask:
 - ✅ Documentation: Complete (May 2026) — cookbook (#190), perf tuning guide (#191), error message guide (#192)
 - 🎯 Phase 9: Ongoing (Ecosystem — tracked in `minigraf-examples` repo; developer tools in `minigraf-inspector` and `minigraf-visualizer`)
 
-**Note**: This is a hobby project. Timeline is flexible but realistic.
+**Note**: This is a solo-maintained project. Timeline is flexible but realistic.
 
 ---