fix(counter): Drop stale ETF/US/SPCX from the embedded directory (#576)

`SPCX.US` resolved to `ETF/US/SPCX` instead of `ST/US/SPCX`, so every
counter_id-based endpoint queried the wrong instrument type:

```
$ longbridge financial-statement SPCX.US --kind IS --report qf
Error: openapi error: code=2601400: internal server error
```

SPCX used to be the AXS SPAC and New Issue ETF, which has since
delisted; the ticker now belongs to SpaceX (a stock). The embedded
directory in `rust/src/utils/US-ETF.csv` is a static snapshot and is
consulted before the remote-resolved cache, so the stale entry always
won and the backend's correct answer never applied.

Removing the entry lets the symbol fall back to the default `ST/`
prefix. Verified against the live API — `financial-statement`, which
previously failed, now returns SpaceX's quarterly income statement.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Author: huacnlee

rust/src/utils/US-ETF.csv

@@ -5916,7 +5916,6 @@ ETF/US/SPCI
 ETF/US/SPCK
 ETF/US/SPCL
 ETF/US/SPCT
-ETF/US/SPCX
 ETF/US/SPCY
 ETF/US/SPCZ
 ETF/US/SPD