Rewrite btcprice from Clojure to Python FastAPI

Replace the Clojure Kit application with a Python FastAPI app that
produces identical HTML output. WebSocket proxy, Danish number
formatting, and HTMX integration all preserved.

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

CLAUDE.md

@@ -1,15 +1,12 @@
 # btcprice
 
-Bitcoin price tracker UI — Clojure Kit web application. Serves the HTML/Tailwind UI. Connects to btcdata for live price data via WebSocket.
+Bitcoin price tracker UI — Python FastAPI web application. Serves the HTML/Tailwind UI. Connects to btcdata for live price data via WebSocket.
 
 ## Build & Development Commands
 
 - `make run` — Start dev server on port 4000
-- `make repl` — Start nREPL
-- `make test` — Run tests
 - `make tailwind` — Watch Tailwind CSS for changes
-- `make uberjar` — Build production JAR
-- `docker compose up -d` — Start btcprice + btcdata containers
+- `make test` — Run tests
 
 ## Docker
 
@@ -22,21 +19,11 @@ Docker runs alongside local dev on different ports:
 
 btcprice's docker-compose includes btcdata via `include: ../btcdata/docker-compose.yml`.
 
-## REPL Commands
-
-```clojure
-(dev-prep!)   ;; Prepare dev system
-(go)          ;; Start system
-(reset)       ;; Reload code & restart
-(halt)        ;; Stop system
-```
-
 ## Architecture
 
-- **Framework:** Kit (Integrant-based)
-- **Server:** Undertow
-- **Routing:** Reitit
-- **Templates:** Hiccup + HTMX (WebSocket extension)
+- **Framework:** FastAPI
+- **Server:** Uvicorn
+- **Templates:** Inline HTML strings + HTMX (WebSocket extension)
 - **Styling:** Tailwind CSS v4
 - **Data backend:** btcdata (separate service at BTCDATA_URL, default http://localhost:4100)
 - **No database** — all data comes from btcdata
@@ -44,21 +31,6 @@ btcprice's docker-compose includes btcdata via `include: ../btcdata/docker-compo
 ## Source Layout
 
 ```
-src/clj/pmagnus/btcprice/
-├── core.clj              # App entry point
-├── config.clj            # System config loader
-└── web/
-    ├── handler.clj       # Ring handler + routes
-    ├── htmx.clj          # page/fragment macros
-    ├── controllers/
-    │   └── health.clj    # Health check
-    ├── middleware/
-    │   ├── core.clj      # Base middleware
-    │   ├── exception.clj # Exception handling
-    │   └── formats.clj   # Content negotiation
-    └── routes/
-        ├── api.clj       # /api routes (JSON)
-        ├── ui.clj        # UI routes (HTML + HTMX WebSocket)
-        ├── ws_proxy.clj  # WebSocket proxy to btcdata
-        └── utils.clj     # Route utilities
+app/
+└── main.py    # FastAPI app: routes, WebSocket proxy, HTML rendering
 ```