kettle-jem: .rspec merge replaces rails_helper require

[pboling]

Bug

kettle-jem templating damaged a destination .rspec file by replacing a Rails-specific loader flag instead of preserving it.

Bad template commit:

• a17317beff6f4e643c0767ca0356d5586597fb51
• commit subject: 🎨 Template bootstrap by kettle-jem v7.1.0
• affected repo/member: galtzo-floss/sanitize_email
• affected file: .rspec

Bad diff shape:

 --format progress
 --color
 --order random
---require rails_helper
+--require spec_helper
+--exclude-pattern spec/tmp/**/*_spec.rb
 --warnings
 --format html
 --out results/test_results.html

Scenario

sanitize_email is a Rails/Combustion-style gem whose suite relies on .rspec loading rails_helper before specs execute. The generated/template .rspec wanted to add --exclude-pattern spec/tmp/**/*_spec.rb, but the merge also changed the existing loader from rails_helper to spec_helper.

That turned a valid destination-specific RSpec option into the template default. The later release/test failure made it look like individual specs needed require "rails_helper", but that was only a symptom of this .rspec template damage.

Observed downstream symptoms included Rails-dependent specs running without the Rails test boot path during kettle-release/kettle-changelog coverage generation, requiring manual workaround edits in spec files.

Expected Behavior

Templating should preserve destination-specific RSpec loader options.

For this input shape, the result should retain:

--require rails_helper

and still add managed template flags such as:

--exclude-pattern spec/tmp/**/*_spec.rb

It should not replace rails_helper with spec_helper.

Likely Cause

The current .rspec merge appears to treat lines textually, without understanding option flags and their arguments. --require rails_helper and --require spec_helper are not two arbitrary independent lines; they are --require flag/value records with loader semantics.

Fixing this properly likely requires a --flag aware parser for .rspec / RSpec option files. We do not currently have that parser.

Regression Test Shape

Add a fixture-based regression with:

Destination .rspec:

--format progress
--color
--order random
--require rails_helper
--warnings
--format html
--out results/test_results.html

Template .rspec containing the template default loader and additive temp-spec exclusion:

--format progress
--color
--order random
--require spec_helper
--exclude-pattern spec/tmp/**/*_spec.rb
--warnings
--format html
--out results/test_results.html

Expected merged .rspec should preserve --require rails_helper and add --exclude-pattern spec/tmp/**/*_spec.rb without downgrading the loader to spec_helper.

Acceptance Criteria

• kettle-jem has a regression spec for the exact .rspec shape above.
• .rspec merge logic is flag-aware enough to treat flag/value pairs as structured records.
• Destination --require rails_helper survives templating.
• The fix does not require adding require "rails_helper" to every affected spec file.

[pboling]

Additional parser requirement: the eventual flag-aware merge logic also needs to distinguish singleton flags from repeatable flags. Some option formats commonly allow repeated flag/value pairs, for example repeated --env KEY=VALUE entries. Those should be merged as multiple records instead of collapsed or replaced as if the flag name alone were unique. The parser/merge policy should define repeatable-vs-singleton behavior per flag where possible, with conservative preservation for unknown repeatable-looking flag/value pairs.