fix: harden qmd error diagnostics

[jayzeng]

Summary

• prevent qmd child processes from inheriting FORCE_COLOR and set NO_COLOR
• strip CSI and OSC control sequences from qmd output and fallback error messages
• make explicit qmd search timeouts configurable with PI_MEMORY_QMD_SEARCH_TIMEOUT_MS (default 60000)
• derive timeout diagnostics from the configured value and report it in memory_status
• update the README link to the current Earendil Pi repository

Testing

• npm test (168 passed)
• npm run build
• npm run lint
• git diff --check

Compatibility

• no changes to on-disk memory formats
• qmd retrieval semantics are unchanged; this only adjusts child-process color configuration, timeout configuration, and error diagnostics