chore(workflows): differentiate Validate and Publish icons

- Change Validate (Dev) icon from 💯 to ✅ for Book and TinyTorch
- Change Update PDFs icon from 📄 to 📑 (bookmark tabs)
- Fix workflow_run references to match exact workflow names

This makes it easier to visually distinguish between Validate and
Publish operations in the GitHub Actions UI.

.github/workflows/book-deploy-preview.yml

@@ -16,7 +16,7 @@ on:
         required: false
         type: string
   workflow_run:
-    workflows: ["📚 Book Validate (Dev)"]
+    workflows: ["📚 Book · ✅ Validate (Dev)"]
     types:
       - completed
 

.github/workflows/book-validate-dev.yml

@@ -1,4 +1,4 @@
-name: '📚 Book · 💯 Validate (Dev)'
+name: '📚 Book · ✅ Validate (Dev)'
 
 # Cancel any running validation and start fresh when new one is triggered
 # Concurrency disabled - allow unlimited parallel builds

.github/workflows/tinytorch-publish-dev.yml

@@ -6,7 +6,7 @@ name: '🔥 TinyTorch · 💯 Publish (Dev)'
 on:
   workflow_dispatch:
   workflow_run:
-    workflows: ["🔥 TinyTorch Validate (Dev)"]
+    workflows: ["🔥 TinyTorch · ✅ Validate (Dev)"]
     types: [completed]
     branches: [dev]
 

.github/workflows/tinytorch-update-pdfs.yml

@@ -1,4 +1,4 @@
-name: '🔥 TinyTorch · 📄 Update PDFs'
+name: '🔥 TinyTorch · 📑 Update PDFs'
 
 # =============================================================================
 # PDF-Only Update Workflow

.github/workflows/tinytorch-validate-dev.yml

@@ -1,4 +1,4 @@
-name: '🔥 TinyTorch · 💯 Validate (Dev)'
+name: '🔥 TinyTorch · ✅ Validate (Dev)'
 
 # =============================================================================
 # TinyTorch Validate (Dev) - Comprehensive Testing Workflow