Add DRY, dependency and SOLID criteria to the code checklists (MIL-009 task 5)

New criteria, appended after the existing ones (nothing renumbered or
changed):

- DRY in all five qc-programming-* checklists (python, c, cpp, csharp, shell)
- dependency rule in all but shell (imports, includes or references point
  inward, no cycles; in C also one responsibility per module)
- SOLID in python, cpp and csharp
- qc-dcd.md criterion 9: dependencies between classes and packages point
  inward (cycles stay with criterion 8)

Each is tagged with an ISO/IEC 25010 characteristic, and the criterion Notes
name the rule in the framework's coding-conventions skill, which defines it
once. Each checklist has a new Proposed Version History row for S02, who
accepts coding-standard changes. Common Defects gain a bullet per criterion.

qc-programming-shell.md

@@ -10,6 +10,7 @@
 | Date | Status | Author | Reviewer | Change | Commit |
 | --- | --- | --- | --- | --- | --- |
 | 2026-10-02 | Accepted | Jens Tirsvad Nielsen | S07 | Initial version | — |
+| 2026-10-09 | Proposed | Jens Tirsvad Nielsen | S02 | Added criterion 15 (DRY) | pending |
 
 ---
 
@@ -37,6 +38,7 @@ Level: **Mandatory** criteria are the baseline every instance must meet; **Optio
 | 12 | Formatted with `shfmt` (or the project's formatter) | Optional | Maintainability | |
 | 13 | Safe to re-run: a second run does not duplicate or corrupt what the first did | Optional | Reliability | |
 | 14 | Bash version and external tools it needs are stated; GNU-only options are named | Optional | Portability | |
+| 15 | A command sequence, constant, path or message used more than once is defined once (a function, a variable or a sourced helper); a helper is shared between scripts only where it expresses the same knowledge | Mandatory | Maintainability | Modularity, Reusability. Rule: `coding-conventions` skill, “State each piece of knowledge once” |
 
 ## Common Defects
 
@@ -47,6 +49,7 @@ Level: **Mandatory** criteria are the baseline every instance must meet; **Optio
 - A token echoed to the terminal or kept in the script
 - No usage message, so a wrong call fails with a cryptic error
 - A script that implements nothing in any task or design
+- The same path, option list or message pasted into several places in one script, or copied between scripts
 
 ## Traceability Rule