feat: make examples cumulative with carry-forward chain and capstone

Add three new sections to all 14 examples:
- "Carry Forward": what output feeds into later examples (01-10)
- "The Cumulative Path": alternative prompt building on previous output (02-10)
- "Now Try It Yourself": personalized template with transferable pattern (all)
- "Building On" callout connecting back to previous examples (02-10)

Add Example 14: Build Your Personal Agent - capstone that guides reader
through writing their own CLAUDE.md, creating a personal skill, connecting
a messaging channel, setting up automation, and testing end-to-end.

Update README with cumulative path diagram, two usage modes, and example 14.
Update GETTING-STARTED.md with cross-references to relevant examples.

17 files changed, 703+ lines added. The examples now form a coherent
learning path from "see what it can do" to "build your own agent."

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

examples/11-computer-use/prompt.md

@@ -52,3 +52,23 @@ works with any application, not just browsers.
 For browser-only automation, Playwright MCP (example 04) is
 faster and more reliable. Computer Use shines when you need to
 interact with native desktop apps that have no API or CLI.
+
+---
+
+## Now Try It Yourself
+
+Think about a desktop task you repeat that involves no API or CLI:
+
+```
+Open [application], navigate to [where], and [do what].
+Take a screenshot before and after. Save the result as
+[filename] on the Desktop.
+```
+
+**The pattern you just learned:** application + navigation + action + capture. Computer Use works with anything visible on screen. The golden rule: if you can do it by clicking, Claude can do it too.
+
+Ideas worth trying:
+- Open your email client, screenshot the inbox, and list unread subjects
+- Fill out a form in a desktop app with data from a file
+- Take a screenshot of a dashboard and summarize the metrics
+- Open a PDF, extract key sections, and save them as markdown