Expose dashboard as a mountable starlette app

[jklaise]

Adds support for #64.

Full disclosure - I'm not familiar with React development, so for the frontend wiring I have relied on ChatGPT. There are also a bunch of formatting changes made automatically by my IDE - I re-ran npm run lint -- --fix but this didn't change the formatting back.

Basic idea:

• Ship chancy-config.js and expose it over the API so that the backend server can tell the (statically bundled) frontend under what prefix it is running
• Provide utilities in config.ts that are used elsewhere to make all route references relative to the base path with the prefix

An example FastAPI app with the dashboard mounted as a subapp:

# app.py
from contextlib import asynccontextmanager

from fastapi import FastAPI

from chancy import Chancy, Worker
from chancy.plugins.api import Api, SimpleAuthBackend

# Configure your Chancy instance as you normally would.
CHANCY_DSN = "postgresql://localhost:5432/dev"

# Auth + path prefix for the mounted dashboard/API
api_plugin = Api(
    authentication_backend=SimpleAuthBackend({"admin": "password"}),
    path_prefix="/chancy",
    allow_origins=["*"],
)

chancy = Chancy(CHANCY_DSN)


@asynccontextmanager
async def lifespan(app: FastAPI):
    async with chancy:
        async with Worker(chancy) as worker:
            # Build the Starlette app once and mount it under the same prefix
            api_app = api_plugin.build_starlette_app(worker, chancy)
            app.mount(api_plugin.path_prefix or "/", api_app)

            yield


app = FastAPI(lifespan=lifespan)


@app.get("/ping")
async def ping():
    return {"pong": True}


if __name__ == "__main__":
    import uvicorn

    uvicorn.run(app, host="127.0.0.1", port=8000)

[codecov]

Codecov Report

❌ Patch coverage is 0% with 25 lines in your changes missing coverage. Please review.
✅ Project coverage is 66.76%. Comparing base (31cc61d) to head (4d45dab).

Files with missing lines	Patch %	Lines
chancy/plugins/api/__init__.py	0.00%	25 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##            26_ux      #76      +/-   ##
==========================================
+ Coverage   66.71%   66.76%   +0.05%     
==========================================
  Files          59       59              
  Lines        3506     3563      +57     
==========================================
+ Hits         2339     2379      +40     
- Misses       1167     1184      +17     

Flag	Coverage Δ
unittests	66.76% <0.00%> (+0.05%)	⬆️

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[TkTech]

This seems reasonable overall. We should probably pass the port through as well.

[TkTech]

Overall I don't see any glaring issues - we should probably pass through the port as well, and we'll need to add a short doc page on mounting under a sub-path.