phase 1: foundations — market structure + liquidity + sessions (35 files)

01-market-structure (12):
  swing-high, swing-low, internal-structure, external-structure,
  bos-bullish, bos-bearish, choch-bullish, choch-bearish,
  mss, mss-vs-choch, range-expansion, range-contraction.

02-liquidity (14):
  buy-side-liquidity, sell-side-liquidity, equal-highs, equal-lows,
  trendline-liquidity, liquidity-pool, liquidity-void,
  liquidity-sweep, liquidity-run, internal-range-liquidity,
  external-range-liquidity, draw-on-liquidity, liquidity-matrix,
  relative-equal-highs-lows.

15-sessions (9):
  session-overview, asia-session, london-session, ny-am-session,
  ny-lunch, ny-pm-session, london-close, session-overlaps,
  session-vs-killzone.

Each file: all required top-matter fields filled, ## Machine-Readable
JSON block, ## Related Concepts cross-links, citations from SOURCES.md.

INDEX.md, TIMELINE.md (2016/2017/2018/2021/2022 backfill), CHANGELOG.md
updated.