Add /M command-line switch for importer selection

[PiJoCoder]

Adds a new /M command-line argument to sqlnexus.exe that lets automation scripts select which importers to run without modifying saved UI settings (user.config is never touched by this path).

Changes:

sqlnexus/Program.cs

• Parse /M where tokens are '+'-separated importer names or the special value "All"
• Populate Globals.EnabledImporters (null when /M is absent, so GUI sessions are completely unaffected)
• Extend ShowUsage() to document /M

sqlnexus/Globals.cs

• Add static HashSet EnabledImporters as the in-memory-only /M override state

sqlnexus/fmImport.cs

• Add READTRACE_IMPORTER_NAME and TRACEEVENT_IMPORTER_NAME constants
• Add TraceEventImporter token to ImporterTokenToName dictionary
• Order TraceEventImporter.dll at priority 150 (after Rowset=100, before ReadTrace=200) in OrderedImporterFiles()
• EnumImporters() now calls EnforceTraceImporterExclusivity() so that if both trace importers are saved as enabled, ReadTrace is automatically disabled (TraceEventImporter is preferred)
• Add helpers: EnforceTraceImporterExclusivity(), IsImporterEnabled(), DisableImporterByName()
• EnumFiles() /M override block:
  • Rowset Importer is always forced on (it populates core tables required by all importers and post-processing scripts)
  • Other importers are gated by the token set
  • If both ReadTrace and TraceEventImporter are requested, TraceEventImporter wins
• tsiBool_Click() enforces mutual exclusivity in the UI: enabling one trace importer automatically disables the other and shows a dialog
• RunPostScripts() now runs ReadTracePostProcessing.sql for both ReadTrace and TraceEventImporter (both write to the ReadTrace schema)

sqlnexus/Properties/Resources.resx + Resources.Designer.cs

• Add Usage_Importers help string documenting /M tokens and examples

Supported /M tokens:
ReadTrace, Perfmon, Linux, Errorlog, TraceEventImporter, CustomXEL, All

Rowset Importer always runs regardless of /M selection. ReadTrace and TraceEventImporter are mutually exclusive; TraceEventImporter takes precedence when both are specified.

Testing:

1. Default behavior — no /M switch (regression check)

Launch SQLNexus normally through the GUI or via a console run without /M. Verify that all importers respect their saved user.config / AppConfig.xml settings exactly as before and that no user.config values are modified after the run.

• Use this query for all scenarios to validate presence of a representative table

  select top 10 * from tbl_SQL_Base_SystemHealthXEL_Startup --validates CustomXEL
  select top 10 * from dbo.CounterData --validates Perfmon
  select top 10 * from tbl_fltmc_instances --validates Rowset importer
  select top 10 * from tbl_ERRORLOG --validates Errorlog
  select top 10 * from ReadTrace.tblBatches --validates ReadTrace or TraceEventImporter

2. /MReadTrace — single importer selection

sqlnexus.exe /S.\SQL2025 /dsqlnexus /E /I"D:\SQLLogScout\output" /X /MReadTrace /N

Expected:

• Log shows Rowset Importer enabled = True (forced on as core dependency)
• Log shows ReadTrace (SQL XEL/TRC Files) enabled = True
• All other importers show enabled = False
• ReadTracePostProcessing.sql executes without schema errors
• PerfStatsAnalysis.sql executes without missing-table errors

3. /MReadTrace — single importer selection

sqlnexus.exe /S.\SQL2025 /dsqlnexus /E /I"D:\SQLLogScout\output" /X /MReadTrace /N

Expected:

• Log shows Rowset Importer enabled = True (forced on as core dependency)
• Log shows ReadTrace (SQL XEL/TRC Files) enabled = True
• All other importers show enabled = False
• ReadTracePostProcessing.sql executes without schema errors
• PerfStatsAnalysis.sql executes without missing-table errors

4. /MAll — all importers enabled

sqlnexus.exe /S.\SQL2025 /dsqlnexus /E /I"D:\SQLLogScout\output" /X /MAll /N

Expected:

• Log shows all importers as enabled = True
• Full import completes including CustomXEL, RawFileImport, PostProcess, PerfStatsAnalysis

5. /MReadTrace+Errorlog — multiple importers

sqlnexus.exe /S.\SQL2025 /dsqlnexus /E /I"D:\SQLLogScout\output" /X /MReadTrace+Errorlog /N

Expected:

• Rowset Importer, ReadTrace, and ERRORLOG Importer are enabled
• Perfmon, Linux, TraceEventImporter are disabled
• Both ReadTrace and ERRORLOG data appear in the database

6. /MTraceEventImporter — managed trace importer

sqlnexus.exe /S.\SQL2025 /dsqlnexus /E /I"D:\SQLLogScout\output" /X /MTraceEventImporter /N

Expected:

• Rowset Importer and TraceEventImporter are enabled
• ReadTrace is disabled (mutual exclusivity)
• ReadTracePostProcessing.sql executes (TraceEventImporter also uses the ReadTrace schema)

7. /MReadTrace+TraceEventImporter — mutual exclusivity via /M

sqlnexus.exe /S.\SQL2025 /dsqlnexus /E /I"D:\SQLLogScout\output" /X /MReadTrace+TraceEventImporter /N

Expected:

• Log shows: /M override; both trace importers selected — disabling 'ReadTrace (SQL XEL/TRC Files)' in favour of 'Trace Event Importer (Managed)'
• Only TraceEventImporter runs; ReadTrace is suppressed

8. GUI mutual exclusivity — enabling one trace importer disables the other

Open the GUI, go to Options → Importers, enable ReadTrace. Then enable Trace Event Importer (Managed).

Expected:

• A dialog appears: "You have enabled 'Trace Event Importer (Managed)'. The 'ReadTrace (SQL XEL/TRC Files)' importer has been automatically disabled..."
• ReadTrace Enabled checkbox becomes unchecked automatically
• Reverse direction (enabling ReadTrace while TraceEventImporter is on) behaves the same way

9. user.config is not modified by /M runs

Run any /M variant, then inspect user.config (typically in %LOCALAPPDATA%...\user.config).

Expected:

• The Enabled values for all importers in user.config are identical before and after the console run