The default mirror root was hard-coded to <projectDir>/mcp-mirror/,
which collides when two .project files live in the same folder
(e.g. \files\...\Multi plc test\ProjectA.project +
ProjectB.project both default to the same mirror -- each
mirror_export call clobbers the other's output).
New resolution rule (preserves backward-compat -- existing setups
unaffected):
- If <projectDir>/mcp-mirror/ already exists, use it
- Else if exactly one .project sibling, use <projectDir>/mcp-mirror/
- Else (multiple .project) use <projectDir>/<basename>_mcp_mirror/
Implemented as src/mirror-paths.ts (TS helper, used by server.ts
maybeOpenMirrorInVscode and unit-testable) plus the same logic
inlined in the Python scripts that need it (mirror_export.py et al.,
no shared-import infra exists CODESYS-side).