[AstroMyth101]

Scope

• Replace generic headings and self-promotional phrases with descriptions of actual engineering work.
• Remove repetitive Value conclusions from selected project case studies.
• Preserve technical figures, project descriptions, navigation, and existing blog posts.
• Correct the gearbox conclusion, which previously claimed every component exceeded a 2.5 safety-factor target although its reported pinion contact and bolt fatigue factors were lower.

Validation

• Eleventy build check on this branch.
• Review final wording and engineering claims before merging.

Copy-only changes. No application logic, dependencies, or CI workflow changes. This PR is intentionally a draft for editorial approval.