`Analyzer.resolveTypeNode` read the array `.length` node's `.int_literal`
union field unconditionally. For a named-const dimension (`MAX :: 4;
[MAX]u8`) that node is an `identifier`, so the access tripped Zig's
checked-union panic and `sx lsp` aborted on didOpen. The main compiler
was unaffected (it folds the dim through the IR).
- New `arrayDimLength` helper switches on the dimension node tag:
int_literal → value; identifier → a recorded module-const int value;
anything else / out-of-u32-range → unknown. Never assumes a node shape.
- `Type.ArrayTypeInfo.length` is now `?u32`; null is an explicit "editor
couldn't fold this dimension" marker (rendered `[_]T`), never a
fabricated concrete length.
- New `const_int_values` registry records integer-literal consts at
registration time for the identifier path.
Regression: first `src/lsp/*.test.zig` (the minimal LSP harness), wired
into the test graph via `src/root.zig`. Drives `analyzeDocument` over
`[MAX]u8` (folds to 4, no panic), `[64]u8` (happy-path guard), and
`[N]u8` (explicit unknown). Fail-before/pass-after verified.
Sibling audit of the resolveTypeNode/fieldType family: the array dim was
the only unchecked union-field access; all other arms recurse or
tag-check first. Noted a non-crashing display gap in server.zig hover
rendering for step B.
