feat(design-system): add Andritz design philosophy reference

[Xuu-an]

Summary

• Add "The Monolithic Engine" design philosophy document as the creative north star for the Andritz Precision design system
• Covers 10 sections: creative north star, no-line rule, glass & gradient rule, tonal architecture (light/dark surface hierarchies), typography blueprint scale, elevation & depth, data zone philosophy, industrial aesthetic rules, do's, and don'ts
• Located at .claude/skills/design-system/references/design-philosophy.md

Test plan

• Verify the markdown renders correctly on GitHub
• Confirm all token values match the existing semantic/primitive token references
• Review design philosophy alignment with component specs and token architecture

🤖 Generated with Claude Code

[mrgoonie]

Cron-safe maintain review: deferring this PR for now rather than merging the standalone philosophy file.

Evidence checked:

• This PR only adds .claude/skills/design-system/references/design-philosophy.md (+112 lines).
• Related open Andritz work already exists: Rebrand design-system skill to Andritz Design System #248 (rebrand SKILL.md), Replace primitive tokens with Andritz industrial design values #251 (primitive tokens), feat: Andritz Precision industrial design system #255 (broad Andritz design-system replacement), and feat: andritz-design-system-v2 — The Monolithic Engine v2 #320 (new andritz-design-system-v2 skill). feat: Andritz Precision industrial design system #255 and feat: andritz-design-system-v2 — The Monolithic Engine v2 #320 both contain fuller Monolithic Engine / Andritz design-system implementations.
• Current main does not contain an Andritz/Monolithic Engine reference, so this is not already merged, but accepting only this file would create orphaned design guidance without the matching token/component/source-of-truth changes.

Decision: deferred / needs consolidation.

Next step: please consolidate this into the chosen Andritz implementation path (prefer a narrow source-of-truth PR, or clearly supersede this with #320 if that separate skill is the intended direction). Once the owner picks the lane, this standalone PR should be retargeted or closed to avoid parallel docs drifting.

[mrgoonie]

Thanks for the contribution. I’m requesting changes because this adds a new design-system reference that is currently not wired into the skill and it introduces token names/values that do not match the existing token docs.

Required changes:

1. Link the new reference from .claude/skills/design-system/SKILL.md in the References table. Right now agents loading the design-system skill read the SKILL.md reference list, and this new references/design-philosophy.md file is not discoverable from that flow.
2. Align the token language with the current design-system token architecture, or add the missing token definitions as part of the same PR. The new doc references surface, surface-container-*, primary, primary-container, on-surface-variant, outline-variant, and on-secondary-fixed, but the existing semantic/primitive token docs in this repo define the current blue/gray CSS-variable model (--color-primary, --color-card, --color-muted, --color-border, etc.). As written, this creates a parallel token vocabulary that consumers cannot validate against the current design-system references.
3. Either remove the unchecked test-plan claims or include a concrete verification step. The PR body says token values should be confirmed against existing semantic/primitive token references, but the added values do not currently appear in those references.

Evidence checked:

• Diff is a single new file: .claude/skills/design-system/references/design-philosophy.md.
• .claude/skills/design-system/SKILL.md References table does not include the new file.
• Existing references/semantic-tokens.md and references/primitive-tokens.md use the repo’s current CSS-variable naming; the new Material-style surface/on-* token names are not defined there.
• Duplicate/prior-work search found related open Andritz PRs (#248, #251, #255), but no exact merged duplicate of this reference doc.

This can be a useful design direction doc, but it needs to be discoverable and token-compatible before merge.

[ia-abatista]

Recommend closing, @mrgoonie. Adds an Andritz-Precision vendor design-philosophy doc to the design-system skill. Part of the off-scope Andritz series (#248-#256, #320).