Add Chi: lightweight idiomatic Go router (~22k ⭐)

[BennyFranciscus]

Chi — stdlib-friendly Go router

Chi (~22k ⭐) is a lightweight, idiomatic router for Go that builds directly on net/http. No custom context types, no framework lock-in — handlers are just http.HandlerFunc.

Why it's interesting

Chi fills the gap between raw stdlib and full frameworks. HttpArena's Go lineup now covers the full spectrum:

Entry	Foundation	Approach
go-fasthttp	fasthttp	Raw custom HTTP
Fiber	fasthttp	Framework on fasthttp
Gin	httprouter + custom Context	Full framework
Echo	Custom radix tree + custom Context	Full framework
Chi	stdlib net/http	Thin router layer

The interesting question: how much does staying close to stdlib cost vs. custom abstractions like Gin's Context or fasthttp's custom HTTP parser?

Implementation

• Chi v5.2.5 on Go 1.24
• Standard net/http server
• modernc.org/sqlite for the /db endpoint (pure Go, no CGO)
• Pre-loaded static files and dataset
• All HttpArena endpoints implemented

Tests

Builds and compiles clean. All standard endpoints implemented.

cc @pkieltyka @VojtechVitek — thought it'd be cool to see how Chi stacks up against the other Go frameworks in HttpArena! Chi's "just a router" philosophy is really interesting for benchmarking since it shows the stdlib baseline with minimal overhead.