feat(foxbit): add X-FB-CLIENT identification headers

[matheus-alcuri-foxbit]

Summary

Sends X-FB-CLIENT: ccxt and X-FB-CLIENT-VERSION: <ccxt version> on every foxbit REST request so the exchange can identify and measure ccxt-originated traffic (client header approach chosen over User-Agent, which users/base code can override).

Since the library version constant was not reachable from transpiled exchange code, this adds a getCcxtVersion() base helper implemented above the transpile marker (hand-written per language: TS/JS, Python, PHP, C#, Go). Headers are injected in sign() (same pattern as bybit's Referer), so they take precedence over user headers overrides. A testFoxbit broker-id test asserts both headers via last_request_headers in all five languages.

Related: foxbit-group/kepler#2902 (server-side metric), foxbit-group/ccxt-foxbit-tests#18 (E2E tests).

Tests run

• npm run lint — pass (0 errors on edited files)
• npm run tsBuild — pass
• npm run transpile (Python + PHP) — pass
• npm run transpileCS + npm run buildCS — pass (dotnet 9, 4 projects, 0 errors)
• npm run transpileGO + npm run buildGO — pass (v4 + v4/pro)
• request tests — 70 passed in JS, Python, PHP, C#, Go
• response tests — 17 passed in JS, Python, PHP, C#, Go
• id-tests (brokerId suite incl. new testFoxbit) — passed in JS, Python, PHP, C#, Go
• test-base-rest — passed in JS and Python (base was touched)
• Python syntax via py_compile; PHP via php -l (php:8.2 container)
• Live smoke: fetchTicker BTC/BRL against api.foxbit.com.br — request carried both headers, 200 OK

Notes

• Diff is source-only: ts/src/** + hand-written base files (python/ccxt/base/exchange.py, php/Exchange.php, cs/ccxt/base/Exchange.Misc.cs, go/v4/exchange_metadata.go, go/v4/exchange_interface.go). Per-exchange generated files are left to the build automation.
• The version header value comes from each language's existing version constant (__version__, Exchange::VERSION, ccxtVersion, Version), all already bumped by vss.
• Follow-up: upstream this to ccxt/ccxt so the headers ship in released packages — real traffic only carries them once users update.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds Foxbit-specific client identification headers to all REST requests, enabling the exchange to attribute CCXT traffic, and introduces a small cross-language base helper to expose the library version for that header value.

Changes:

• Injects X-FB-CLIENT: ccxt and X-FB-CLIENT-VERSION: <ccxt version> in foxbit REST request signing.
• Adds a getCcxtVersion()/get_ccxt_version() helper across the base classes in TS + transpiled languages.
• Extends the brokerId test suite with an offline testFoxbit assertion that validates both headers via last_request_headers.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
ts/src/test/tests.ts	Adds testFoxbit() to the brokerId suite and asserts the two Foxbit headers from last_request_headers.
ts/src/foxbit.ts	Adds Foxbit client identification headers in sign() for all REST requests.
ts/src/base/Exchange.ts	Introduces getCcxtVersion() in the TS base exchange class (used by foxbit.sign()).
python/ccxt/base/exchange.py	Adds get_ccxt_version() returning __version__ for Python runtime parity.
php/Exchange.php	Adds get_ccxt_version() returning static::VERSION for PHP runtime parity.
cs/ccxt/base/Exchange.Misc.cs	Adds getCcxtVersion() returning ccxtVersion for C# runtime parity.
go/v4/exchange_metadata.go	Adds GetCcxtVersion() returning Version for Go runtime parity.
go/v4/exchange_interface.go	Adds GetCcxtVersion() to ICoreExchange so Go callers/tests can access it uniformly.

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