issue #2683 : Naming Scheme metadata

[mattcasters]

Summary

First version of Naming Scheme metadata for issue #2683: reusable rules to normalize identifiers (Hop fields, transform/action/pipeline/workflow/metadata names, variables, database tables/columns, files, and folders).

Apply from the GUI without adding buttons to every dialog:

• N indicator on name widgets — click to open the matching scheme in a dialog (creates one of the widget type if none exists)
• CTRL-SHIFT-N (and CTRL-SPACE on fields that do not accept variables) rewrites the current identifier
• TableView toolbar — apply a scheme to a whole column (with undo)
• Get Fields on CSV/Text File Input (and other annotated name columns) can auto-apply

A General scheme is offered on every name field that does not have a type-specific scheme. File schemes rewrite only the last path segment and keep the parent and extension (/data/Order ID.csv → /data/order_id.csv). Folder schemes rewrite the last segment. Transform/action schemes can use a space separator and capitalize the first word (Check db connections).

Plugin kinds (hop-field, hop-transform, file, …) can be extended by other plugins (for example hop-data-vault) without changing Hop.

CI: hop naming-check and pipeline/workflow Verify report names that would change when the matching scheme is applied.

How to try

1. Create a Naming Scheme in the Metadata perspective (or click N on any name field — if none exist, Hop creates one of that type).
2. Default options give e.g. Order ID → order_id. For action/transform names, try lower case + space + capitalize first word.
3. Focus a name field and press CTRL-SHIFT-N, or click N to review the scheme.
4. Open CSV File Input fields and use Apply a Naming Scheme to a column on the TableView toolbar; Undo reverts.

Test plan

• NamingEngineTest (path/extension, space separator, capitalize first word)
• NamingSchemeShortcutTest, NamingSchemeSelectorTest, NamingSchemeValidatorTest
• GuiElementsNamingSchemeTypeTest (FILENAME/FOLDER inference)
• Module + core/ui build; isolated-display UI tests; Spotless clean
• Manual: create scheme from N on an action name; apply CTRL-SHIFT-N; Save As filename; metadata editor N opens a dialog not a tab

Fixes #2683