feat(commands): /update-skills syncs forks with upstream via 3-way merge

Upstream releases fixes worth pulling into the forks (arch-decide, playwright-js, playwright-py) without losing our local modifications. Each fork now has a manifest at upstreams/<name>/ plus a committed baseline snapshot that is the 3-way merge base. scripts/update-skills.py classifies each file's drift and merges to stdout. The command owns per-file confirmation, per-hunk conflict prompts, and every target write.

I centralized manifests under upstreams/ instead of per-skill dotfile dirs because arch-decide is now two flat files in commands/ and can't carry one. A "files" map in its manifest handles the upstream rename of SKILL.md to arch-decide.md.

I seeded baselines from today's upstream HEADs, so pre-existing local modifications classify as local-only from here on. git merge-file signals hard errors as exit 255, which subprocess reports as positive. The guard treats anything 128 and up as an error so a binary-file failure isn't misread as a conflict.

1 files changed, 33 insertions, 0 deletions

diff --git a/upstreams/playwright-py/baseline/examples/static_html_automation.py b/upstreams/playwright-py/baseline/examples/static_html_automation.py
new file mode 100644
index 0000000..90bbedc
--- /dev/null
+++ b/upstreams/playwright-py/baseline/examples/static_html_automation.py
@@ -0,0 +1,33 @@
+from playwright.sync_api import sync_playwright
+import os
+
+# Example: Automating interaction with static HTML files using file:// URLs
+
+html_file_path = os.path.abspath('path/to/your/file.html')
+file_url = f'file://{html_file_path}'
+
+with sync_playwright() as p:
+    browser = p.chromium.launch(headless=True)
+    page = browser.new_page(viewport={'width': 1920, 'height': 1080})
+
+    # Navigate to local HTML file
+    page.goto(file_url)
+
+    # Take screenshot
+    page.screenshot(path='/mnt/user-data/outputs/static_page.png', full_page=True)
+
+    # Interact with elements
+    page.click('text=Click Me')
+    page.fill('#name', 'John Doe')
+    page.fill('#email', 'john@example.com')
+
+    # Submit form
+    page.click('button[type="submit"]')
+    page.wait_for_timeout(500)
+
+    # Take final screenshot
+    page.screenshot(path='/mnt/user-data/outputs/after_submit.png', full_page=True)
+
+    browser.close()
+
+print("Static HTML automation completed!")
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