Skip Solana keypair test when solders is absent; add CI

[Pattermesh]

What

Two changes:

1. Fix a brittle test. tests/test_solana_connector.py::TestSolanaWallet::test_generate_new_wallet hard-failed whenever the optional solders dependency was not installed. Without solders, SolanaWallet() falls back to a stub wallet with pubkey = "STUB_PUBKEY" (11 chars), but the test asserts len(wallet.pubkey) > 30 (a real base58 pubkey). The test now guards with pytest.importorskip("solders"), so it skips gracefully instead of failing when the dep is absent.

2. Add CI. New .github/workflows/ci.yml runs python -m pytest -q on every push and PR to main, across Python 3.10 / 3.11 / 3.12. solders is intentionally not installed in CI, which exercises the new skip path.

Why

solders is an optional dependency (the Solana connector degrades to a stub without it). A missing optional dep should not turn the whole suite red. There was also no CI, so regressions could land silently.

Verification

With solders absent (the default environment), python3 -m pytest -q:

SKIPPED [1] tests/test_solana_connector.py:14: could not import 'solders': No module named 'solders'
99 passed, 1 skipped in ~1s

The previously-failing test now skips; the other 99 tests pass.

🤖 Generated with Claude Code

[abhicris]

Welcome to kcolbchain, @Pattermesh — glad you're here. 🌱

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