fix(dashboard): resolve API origin correctly in docker-compose

[shiv19]

Summary

• Dashboard SSR fetches (e.g. GET /health/env) always resolved the API origin from a static runtime-target table, which defaults to http://localhost:4000. Inside the dashboard container that never reaches the api container, so every docker compose up fails with Cannot resolve deployment info: GET /health/env is unreachable ... ECONNREFUSED.
• INTERNAL_API_URL already existed as an override in apps/dashboard/src/lib/server/api.ts, but was only honored when NEXT_PUBLIC_API_PROXY=true — a NEXT_PUBLIC_* build-time flag the dashboard Dockerfile never sets, so the override was effectively dead code in this deployment path.
• Loosened getServerApiBaseUrl to honor INTERNAL_API_URL unconditionally for server-side requests (browser-side resolution is untouched), and set it in docker-compose.yml to the in-cluster DNS name (http://api:4000) for the dashboard service — matching the same pattern already used for api's own DATABASE_URL/REDIS_URL overrides.

Test plan

• docker compose up -d --build dashboard — dashboard boots clean, no ECONNREFUSED / health/env error in logs
• curl http://localhost:3001 returns a normal redirect instead of the fatal error page
• Maintainers verify no regression for non-docker (bare-metal/desktop) OPENSHIP_LOCAL_API_URL and proxy-mode (NEXT_PUBLIC_API_PROXY=true) paths, which are unaffected in code review but worth a sanity check

[shiv19]

The dashboard wasn't really loading for me after docker compose up without this fix.

[Hydralerne]

Reviewed it - fix looks right, http://api:4000 matches the compose service and the SSR-direct routing makes sense. Two things first:

1. The JSDoc on getServerApiBaseUrl() still says the INTERNAL_API_URL short-circuit only kicks in when NEXT_PUBLIC_API_PROXY=true — not true anymore after this, so update it.
2. This makes INTERNAL_API_URL work regardless of the proxy flag. Can you check the SaaS build doesn't set it somewhere that relies on per-request origin? Would bypass it for SSR. Self-host path is fine.