test: cover workspace symbol aliases

[b3417]

Adds regression coverage for workspace symbol aliases and keeps the symbol matching flow returning aliases as expected.\n\n/claim #263\nCloses #263

[b3417]

Verification update after rebase onto current main:

• cargo test workspace_symbols_include_aliases -- --nocapture → passed
• cargo test test_simple_tree -- --nocapture → passed
• branch force-pushed to the fork with the rebased head

This keeps PR #470 in the ready-for-review bucket.

[b3417]

Checking in on this one. There are no CI checks configured on this PR, and the branch has no merge conflicts. It's ready for review whenever you have time. If you'd prefer a different approach, or if this is no longer relevant, just say so and I'll close it myself.