Per-project access control + UI/feedback/admin refinements

Access control:
- project_members table; non-admins only see/operate on assigned
  projects (enforced across projects, SOPs, work packages — 403 else),
  admins bypass. Creating a project auto-grants its creator access.
- Admin API to get/set a user's project assignments, plus a checkbox
  assignment dialog in the Admin Console user list.

UI / workflow:
- Login page: drop the "Prime Controls" wordmark next to the logo.
- SOP tool: remove emoji icons from buttons and nav tabs.
- Rename "Step Comments" to "Feedback"; the author auto-populates
  (read-only) from the signed-in user.
- Move usage-log viewing to the Admin Console; add an admin card that
  lists all feedback/comments (who, what, page + step, when).
- Sample project name -> "Micron FMCS Install (sample)".

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

html/login.html

@@ -76,7 +76,6 @@
   <main class="card">
     <div class="brand">
       <img src="prime-controls-logo.jpg" alt="Prime Controls" onerror="this.style.display='none'">
-      <span class="name">Prime Controls</span>
     </div>
     <h1>Sign in</h1>
     <p class="sub">Work Package Suite</p>