Task: Document Skew Stickiness Ratio knowledge page

Add a knowledge page under doc/knowledge/domain explaining what happens to an implied volatility surface when spot moves: the two classical rules (sticky strike, sticky delta), the third regime (sticky local volatility), the Skew Stickiness Ratio that measures where a real market sits between them, the adjusted delta and gamma, and the desk-practice view of computing smile deltas. Wire the page into the knowledge index and the related volatility pages.

• A new knowledge page titled "Volatility: Skew Stickiness Ratio" exists under doc/knowledge/domain with Summary, Detail, Source and See also sections.
• The page defines sticky strike, sticky delta, sticky local volatility and the SSR, with the maths in LaTeX, without redefining concepts covered by existing pages.
• The page is linked from the knowledge index and from the Volatility, FX Volatility Surface, and Volatility surface driving pages as appropriate.
• The page cites more than one source: the LinkedIn post and deck by Kshitij Anand plus the standard literature (Derman, Bergomi, Fukasawa, Vargas/Dao/Bouchaud, Balland, Daglish/Hull/Suo).
• The site builds and serves the page.

• Scaffold the page with compass, following the knowledge-doc recipe.
• Research the concept across the web (Derman's regimes, Bergomi's SSR literature, arXiv) so the page does not rest on a single source.
• Review rounds with the user, then a site build served over LAN for visual review.
• Retrofitted as a task when the out-of-band branch became a PR.

Manual QA scenarios (scaffolded via compass add test_scenario, run through the QA Validation Runner panel) that verify this task. Link new ones here as they're created; the scenario doc itself links back via its "Verifies task" field.

Knowledge page Volatility: Skew Stickiness Ratio added under doc/knowledge/domain, wired into the knowledge index, the Volatility page and the Volatility surface driving page. The page covers the two classical surface-dynamics rules plus Derman's third regime, the SSR and its literature (Bergomi ch. 9.4, Fukasawa, Vargas/Dao/Bouchaud), the adjusted delta and total gamma with the ATM vs fixed-strike framings, asset-class notes, desk practice (smile-delta conventions, spot ladders), a numerical example and ORE Studio storage notes. Sourced from the Anand post/deck and the standard literature. Site build clean and served for review.