docs: add auto model, document attachment, and new command aliases

- Add 'auto' model option tip to the Switching Models section in Ch01:
  users can select 'auto' from /model to let Copilot choose the best
  model automatically (v1.0.32)
- Update Session command table in Ch01 with /reset alias for /clear,
  /continue alias for /resume, and /export alias for /share (v1.0.33)
- Update Help and Feedback table in Ch01 with /release-notes alias for
  /changelog and /bug alias for /feedback (v1.0.33)
- Add Attaching Document Files section to Ch02 with examples and a tip
  showing how to use @ to attach PDFs and other supported documents to
  prompts for Copilot to read and reason about (v1.0.32)
- Update Ch02 key takeaways to mention document file support
- Add document files entry to the Ch02 optional topics navigation table

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: DanWahlin

01-setup-and-first-steps/README.md

@@ -433,16 +433,16 @@ That's it for getting started! As you become comfortable, you can explore additi
 
 | Command | What It Does |
 |---------|--------------|
-| `/clear` | Abandons the current session (no history saved) and starts a fresh conversation |
+| `/clear` (or `/reset`) | Abandons the current session (no history saved) and starts a fresh conversation |
 | `/compact` | Summarize conversation to reduce context usage |
 | `/context` | Show context window token usage and visualization |
 | `/new` | Ends the current session (saving it to history for search/resume) and starts a fresh conversation. |
-| `/resume` | Switch to a different session (optionally specify session ID) |
+| `/resume` (or `/continue`) | Switch to a different session (optionally specify session ID) |
 | `/rename` | Rename the current session (omit the name to auto-generate one) |
 | `/rewind` | Open a timeline picker to roll back to any earlier point in the conversation |
 | `/usage` | Display session usage metrics and statistics |
 | `/session` | Show session info and workspace summary |
-| `/share` | Export session as a markdown file, GitHub gist, or self-contained HTML file |
+| `/share` (or `/export`) | Export session as a markdown file, GitHub gist, or self-contained HTML file |
 
 ### Display
 
@@ -455,8 +455,8 @@ That's it for getting started! As you become comfortable, you can explore additi
 
 | Command | What It Does |
 |---------|--------------|
-| `/changelog` | Display changelog for CLI versions |
-| `/feedback` | Submit feedback to GitHub |
+| `/changelog` (or `/release-notes`) | Display changelog for CLI versions |
+| `/feedback` (or `/bug`) | Submit feedback or report a bug to GitHub |
 | `/help` | Show all available commands |
 
 ### Quick Shell Commands
@@ -486,6 +486,8 @@ copilot
 
 > 💡 **Tip**: Some models cost more "premium requests" than others. Models marked **1x** (like Claude Sonnet 4.5) are a great default. They're capable and efficient. Higher-multiplier models use your premium request quota faster, so save those for when you really need them.
 
+> 💡 **New: `auto` model**: You can select `auto` from the `/model` picker to let Copilot automatically choose the best available model for each session. This is a great starting option if you're unsure which model to pick — Copilot will adapt based on what's available to you.
+
 </details>
 
 ---

02-context-conversations/README.md

@@ -427,6 +427,7 @@ These topics build on the essentials above. **Pick what interests you, or skip a
 | Token limits and `/compact` | [Understanding Context Windows](#understanding-context-windows) |
 | How to pick the right files to reference | [Choosing What to Reference](#choosing-what-to-reference) |
 | Analyzing screenshots and mockups | [Working with Images](#working-with-images) |
+| Attaching PDFs and other documents | [Attaching Document Files](#attaching-document-files) |
 
 <details>
 <summary><strong>Additional @ Patterns & Session Commands</strong></summary>
@@ -687,6 +688,22 @@ copilot
 
 > 📖 **Learn more**: See [Additional Context Features](../appendices/additional-context.md#working-with-images) for supported formats, practical use cases, and tips for combining images with code.
 
+<a id="attaching-document-files"></a>
+
+### Attaching Document Files
+
+You can also attach supported document files (such as PDFs) to your prompts using the same `@` syntax. This is handy for providing specs, design documents, or reference material that Copilot can read and reason about alongside your code.
+
+```bash
+copilot
+
+> @requirements.pdf Summarize the key requirements and check if @samples/book-app-project/book_app.py covers them
+
+> @design-doc.pdf What features are described here that are missing from @samples/book-app-project/
+```
+
+> 💡 **Tip**: Document attachment works great for onboarding — paste a spec or design doc and ask Copilot to map it to your existing code.
+
 </details>
 
 ---
@@ -856,12 +873,13 @@ copilot --add-dir /path/to/directory
 
 ## 🔑 Key Takeaways
 
-1. **`@` syntax** gives Copilot CLI context about files, directories, and images
+1. **`@` syntax** gives Copilot CLI context about files, directories, images, and documents
 2. **Multi-turn conversations** build on each other as context accumulates
 3. **Sessions auto-save**: use `--continue` or `--resume` to pick up where you left off
 4. **Context windows** have limits: manage them with `/clear`, `/compact`, `/context`, `/new`, and `/rewind`
 5. **Permission flags** (`--add-dir`, `--allow-all`) control multi-directory access. Use them wisely!
 6. **Image references** (`@screenshot.png`) help debug UI issues visually
+7. **Document files** (like PDFs) can be attached with `@` to give Copilot specs, designs, or reference material
 
 > 📚 **Official Documentation**: [Use Copilot CLI](https://docs.github.com/copilot/how-tos/copilot-cli/use-copilot-cli) for the complete reference on context, sessions, and working with files.