fix(web): default mgmt proxy to the HTTPS self-signed mgmt API

The mgmt API serves HTTPS with the host's self-signed identity cert and requires
mTLS-or-bearer auth (the mTLS work), but the web console's proxy still defaulted to
`http://127.0.0.1:47990` — so a deployment copying .env.example got a plain-HTTP
request to an HTTPS port (→ 502 Bad Gateway, observed live on the Bazzite box).

- .env.example + server/util/auth.ts + vite.config.ts: default PUNKTFUNK_MGMT_URL to
  https://127.0.0.1:47990.
- vite dev proxy: `secure: false` (the host cert is self-signed).
- Document that the deployment needs PUNKTFUNK_MGMT_TOKEN (matching the host's) and
  NODE_TLS_REJECT_UNAUTHORIZED=0 — the web server's only outbound TLS is the loopback
  hop to the host's own self-signed cert, so disabling verify there is scoped + safe.

The running Bazzite box is already fixed live (web.env → https + token + cert-skip,
verified: login 200, /api/v1/status 200). This makes fresh deployments correct.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/README.md

@@ -15,8 +15,9 @@ Query** through **orval** codegen from the OpenAPI spec · **shadcn/ui** (Tailwi
 bun install               # runs `prepare` → codegen (orval + paraglide)
 bun run dev               # http://localhost:3000
 
-# The dev server proxies /api → http://127.0.0.1:47990 (the host's management API).
-# Point it elsewhere: PUNKTFUNK_MGMT_URL=http://<host>:47990 bun run dev
+# The dev server proxies /api → https://127.0.0.1:47990 (the host's mgmt API; it serves HTTPS
+# with the host's self-signed identity cert — the dev proxy uses `secure: false`).
+# Point it elsewhere: PUNKTFUNK_MGMT_URL=https://<host>:47990 bun run dev
 ```
 
 Start a host with the management API up:
@@ -37,7 +38,10 @@ If the host runs with `--mgmt-token`, set it under **Settings → API token** (s
 bun run build             # → .output/  (Nitro server, `bun` preset, + .output/public assets)
 PORT=3000 HOST=0.0.0.0 \
   PUNKTFUNK_UI_PASSWORD=… PUNKTFUNK_MGMT_TOKEN=… \
+  PUNKTFUNK_MGMT_URL=https://127.0.0.1:47990 NODE_TLS_REJECT_UNAUTHORIZED=0 \
   bun run start           # = bun run .output/server/index.mjs
+# (the mgmt API is HTTPS w/ the host's self-signed cert on loopback → the proxy's fetch needs
+#  NODE_TLS_REJECT_UNAUTHORIZED=0; it makes no other outbound TLS calls. See .env.example.)
 bun run lint              # tsc --noEmit
 ```