0.6.0

Added

• Worked walkthroughs under examples/walkthroughs/: a QC pass that finds
  the planted density gap, washout, and gamma ray spike; a cross-well
  comparison surfacing the depth overlap, the missing sonic curve, and the
  neutron unit mismatch; and a short unit-conversion document.

  Every value in them — every depth, every statistic, every JSON block — is
  produced by calling the real tools against a freshly generated well.
  Nothing is transcribed by hand. make walkthroughs regenerates them, and
  both the test suite and CI fail if the committed copies drift from what the
  tools currently return, so the most visible docs in the repo cannot rot into
  a documented lie.

  The documents lead with what was deliberately planted, and the manifest
  table proving it, so a reader can check the tools found what was actually
  there instead of taking the output on faith.