fix(lsp): read self.context_state instead of stale local variable in _context_get_or_load

[jthurlburt]

Summary

• _context_get_or_load captures self.context_state into local variable state at line 1065
• After _create_lsp_context() or _ensure_context_for_document() successfully updates self.context_state to ContextLoaded, the final check at line 1077 reads the stale local state (still NoContext) instead of self.context_state
• This causes the method to always raise RuntimeError("Context failed to load") on the first didOpen, even when context loading succeeds

Impact

The LSP logs "Loaded SQLMesh Context" then immediately crashes on the first textDocument/didOpen. In VS Code, this puts the extension client into a permanent "Client got disposed and can't be restarted" state. Affects both the specified_paths code path (via initializationOptions.project_paths) and the _ensure_context_for_document fallback path.

Fix

Read self.context_state instead of the stale local state variable on lines 1077-1078.

Regression test

Added two tests to tests/lsp/test_context.py that call _context_get_or_load starting from NoContext, covering both affected code paths:

• test_context_get_or_load_from_no_context_with_specified_paths — the specified_paths path
• test_context_get_or_load_from_no_context_via_workspace_folder — the _ensure_context_for_document fallback path

Both fail with RuntimeError("Context failed to load") on the unpatched code and pass with the fix.

Test Plan

• Verified fix locally — LSP hover, go-to-definition, references, and diagnostics all work after patch
• make style passes (ruff, ruff-format, mypy, valid migrations)
• Confirmed bug is present on upstream main
• Added regression tests that fail without the fix and pass with it
• Rebased onto latest main and re-verified

[StuffbyYuki]

@jthurlburt Thanks for the PR!

Approve with one optional ask question - do you think it'd be beneficial to add a small regression test in tests/lsp/ that calls _context_get_or_load starting from NoContext with specified_paths set? That would prevent this from coming back.