Include mssError() when used

[Lightning11wins]

Some files call msError() without including cxlib/mtsession.h. This latent mistake caused compiler errors when I made an otherwise safe change in code I plan to commit to for #77 once it's not being reviewed.

I'm making this a new PR because I don't want to mix even more mostly unrelated changes into the dups branch, and I think these changes will be obviously safe on their own, so they should be trivial to review, approve, and merge.

[greptile-apps]

Greptile Summary

This PR adds the missing #include "cxlib/mtsession.h" header to 10 source files that call mssError() without previously declaring it, fixing latent compiler errors. It also removes trailing blank lines from several files. No logic is changed.

Confidence Score: 5/5

This PR is safe to merge — it makes no logic changes, only adds missing header includes.

All changes are mechanical header additions to files that already use mssError(). No logic, no data flow, and no behavior is altered.

No files require special attention.

Important Files Changed

Filename	Overview
centrallix/cxss/cxss_credentials_db.c	Added missing #include cxlib/mtsession.h for mssError() usage; removed trailing newline.
centrallix/cxss/cxss_crypto.c	Added missing #include cxlib/mtsession.h for mssError() usage; removed trailing newline.
centrallix/cxss/cxss_util.c	Added missing #include cxlib/mtsession.h for mssError() usage; removed trailing newline.
centrallix/objectsystem/obj_content.c	Added missing #include cxlib/mtsession.h for mssError() usage; removed trailing newline.
centrallix/objectsystem/obj_session.c	Added missing #include cxlib/mtsession.h for mssError() usage; removed trailing newline.
centrallix/utility/obfuscate.c	Added missing #include cxlib/mtsession.h for mssError() usage; removed two trailing newlines.
centrallix/utility/param.c	Added missing #include cxlib/mtsession.h for mssError() usage; removed trailing newline.
centrallix/utility/ptod.c	Added missing #include cxlib/mtsession.h for mssError() usage; removed trailing newline.
centrallix/wgtr/apos.c	Added missing #include cxlib/mtsession.h for mssError() usage.
centrallix/wgtr/wgtr.c	Added missing #include cxlib/mtsession.h for mssError() usage.

_{Reviews (3): Last reviewed commit: "Include "cxlib/mtsession.h" everywhere m..." | Re-trigger Greptile}

[Lightning11wins]

Cleared for human review.

[Lightning11wins]

This PR is cleared for human review.

[gbeeley]

Looks good - thanks!