fix: audit SQL construction and general exception catches (CA2100, CA1031)

[DeepDiver1975]

Part of the analyzer-hardening effort (see #153 for rule scoping).

CA2100 (12 sites) — audited, then suppressed per helper.
Every SQL statement is built exclusively from compile-time schema constants (table/column names in Migrations, MasterDataStore, IncidentRepository) or literal PRAGMA statements; all data values flow through bound parameters ($v/$t/$c). No user input ever reaches CommandText. Each helper is marked with a justified SuppressMessage:

• IncidentRepository ReadRow/ReadAll/Run/Exec
• MasterDataStore ReadColumn/Run/Exec, Migrations.Exec, SchemaHelpers AddColumnIfMissing/ColumnExists, SqliteConnectionFactory.Execute
• test: MigrationForwardCompatTests version-marker SQL now binds the value instead of interpolating it

CA1031 (13 sites) — all deliberate, documented broad catches; each carries a justified SuppressMessage because narrowing the exception types would change the documented behavior:

• UI resilience (error banner instead of crash): About/Files/Home/IncidentWorkspace/Links/MasterDataEditor (Import + Export)
• Best-effort services: StorageProviderFileDialogService.ResolveStartLocation, SystemAlarmService Play/TempFileFor/TryLoad
• Try-read semantics: IncidentFileStore.TryReadBytes, IncidentRepository.TryReadState
• TestDoubles.InvokeAsync (test fixture): exceptions delivered via TaskCompletionSource, not swallowed

Verification: harness build (--no-incremental, AnalysisMode=All) shows CA2100 = 0 and CA1031 = 0 with 0 errors and no new warnings in any other rule; all 801 tests pass.