Add missing projects from serendipitylabs.in

…t, Twitter)

- Replace prose bio with $ command / output blocks (whoami, career.log,
  education.log, notes.md, ls elsewhere/, contact.sh)
- Use divs instead of pre so long lines wrap naturally on mobile instead
  of breaking fixed-width column alignment
- Stack career/education rows on narrow screens instead of squeezing
  fixed min-width columns
- Fix dark-mode link hover: override the base theme's solid block
  highlight with a subtle glow + underline consistent with existing
  dark-mode link color

hugo --minify strips whitespace between adjacent inline tags, which
collapsed spans like <span class=sh-key>ML Lead</span><span
class=sh-sep>@ Avalara</span> straight into the following text with no
separator (e.g. 'ML Lead@ Avalaradocument understanding'). This was
invisible in hugo server (no minify) but broke on the deployed build.
Fix: use explicit ' — ' and &nbsp; separators that survive minification
instead of relying on collapsible whitespace between tags.

- Remove invalid RDFa BreadcrumbList/ListItem markup from nav menu
  (was missing required itemListElement, and mismarked site nav as
  a breadcrumb trail)
- Add proper JSON-LD BreadcrumbList in structured_data.html built
  from each page's actual ancestor chain (Home > Section > Page)
  with position/name/item on every entry

.Ancestors is not available in Hugo 0.102.0 (the version pinned in
CI), causing the build to fail. Walk up via .Parent instead, which
is supported across all relevant Hugo versions.

- New essay: The Flat Part of the Curve
- Add math.html partial loading KaTeX from CDN (with SRI) only on
  pages that set 'math: true' in front matter
- Wire the partial into baseof.html

KaTeX is loaded client side rather than using Hugo's native math
support, since CI pins Hugo 0.102.0 which predates the goldmark
passthrough extension.

A short piece computing CAGR from masala dosa prices observed
between 2005 and 2026. Uses the opt-in KaTeX math rendering.