PDX-0: refactor(mcp): change org_describe workspace discovery paths

[Provar-tarunprashar]

RCA: org_describe resolved the Provar workspace via a sibling workspace- dir; the layout needed updating so the project's parent directory is treated as the workspace root.
Fix: workspaceCandidates now yields /, /Provar_Workspaces/workspace-/, and ~/Provar/workspace-/; discoverWorkspace requires a .metadata dir so candidate 1 falls through when the parent is not a workspace; removed the now-unused projectNameDashes helper and updated tests and docs.

[mrdailey99]

Superseding this in favour of #233.

#233 builds directly on your commit (preserved and credited there) but makes the workspace-discovery change additive instead of a replacement: it keeps the sibling <parent>/workspace-<basename>/ layout discoverable (restored as candidate 2, gated on .metadata) so existing sibling-layout users don't regress, and it also syncs the stale in-tool MCP description that still advertised the old <name-dashes> algorithm.

We reproduced the customer's real layout and confirmed your root cause: PDX-515 fixed the SfObject cache parsing, but discovery still pointed at a non-existent sibling dir, so the parser never ran for the parent-layout. Your fix is the missing half — thank you for the RCA and the patch, @Provar-tarunprashar. Please follow along on #233.