feat(profiles): build member profile pages and edit flow

Summary

Build the member profile system — public-facing profile pages (GH + LinkedIn style) and an edit interface for members to manage their own information.

Requirements

Public Profile Page (/members/:slug)

• Profile photo (large, rounded)
• Name, pronouns, headline/title
• Institution with link
• Bio/about section
• Social links: GitHub, LinkedIn, ORCID, personal website
• Research interests as tags
• Working group and affinity group memberships
• Member since date
• Clean, editorial layout (not a generic card)

Edit Profile (/settings/profile)

• Form for all profile fields with real-time validation
• Profile photo upload (crop/resize before upload)
• Slug/URL customization (e.g., /members/cordero-core)
• Preview mode (see what others will see)
• Auto-save or explicit save with success feedback
• Delete account option with confirmation

Member Directory (/members)

• Searchable, filterable list of all public profiles
• Filter by institution, working group, research interest
• Responsive grid of member cards (photo + name + title)

Context

Parent issue: #1916
Depends on: #1917 (schema), #1918 (auth — need signed-in user context)

Implementation Notes

• Profile photos: presigned upload to S3-compatible storage (or Cloudflare R2)
• Slug generation: auto from name, editable, unique constraint in DB
• Design should match the editorial typography style of the rest of the site
• Profile page is the most visible piece — invest in the design

Start by reading the requirements in this issue and the dependency issues #1917 (schema) and #1918 (auth). Map the public profile, edit flow, and member directory before implementation; done means the listed profile fields, uploads, editing, preview, account deletion, search, filters, and responsive cards are supported.