MEIER-225: add docs social metadata and _property attribute helper

[andymeierdev]

Summary

• add social/share metadata to docs layout head (canonical, description, Open Graph, and Twitter/X card tags)
• include page-aware canonical and og:url values based on current path
• add Html._property attribute helper in FSharp.ViewEngine for first-class Open Graph meta usage
• use _property in docs views for OG tags

Validation

• dotnet build sln/src/Docs/Docs.fsproj -nologo (passes locally)

[github-actions]

🍹 preview on fsharp-view-engine/prod

Pulumi report

View in Pulumi Cloud

  Previewing update (prod)

View Live: https://app.pulumi.com/meiermade/fsharp-view-engine/prod/previews/2aafff40-b69e-4dc7-ac68-4bf91e354853

pulumi:pulumi:Stack: (same)
  [urn=urn:pulumi:prod::fsharp-view-engine::pulumi:pulumi:Stack::fsharp-view-engine-prod]
  ~ docker-build:index:Image: (update)
      [id=sha256:7dce1dac725cac480a57d3912a6d0747a6e506fead31a37c5d0e1cf2750b1959]
      [urn=urn:pulumi:prod::fsharp-view-engine::docker-build:index:Image::fsharpviewengine]
    - contextHash: "b79d87cab529cc6158742bf0e63aaaf14d9ab26c64415076932c31d54470cf87"
  ~ kubernetes:apps/v1:Deployment: (update)
      [id=fsharpviewengine/fsharpviewengine]
      [urn=urn:pulumi:prod::fsharp-view-engine::kubernetes:apps/v1:Deployment::fsharpviewengine]
    ~ spec: {
        ~ template: {
            ~ spec: {
                ~ containers: [
                    ~ [0]: {
                            ~ image: "941377122014.dkr.ecr.us-east-1.amazonaws.com/fsharpviewengine:latest@sha256:0431eeaf0bde2f90a171d29276ac0b228b90b5f068f59d3d5639db178c78b1be" => [unknown]
                          }
                  ]
              }
          }
      }
Resources:
  ~ 2 to update
  10 unchanged