docs(meanderaw): 📝 define the lattice address and record the decision

[JimmyPaolini]

Parent

#664

What to build

The vocabulary and the reasoning are written down where the rest of this project's are.

Glossary. The Unit space entry keeps "materialized and enumerable for mosaic, latent
for every other family" — that is still true — and drops the inference "which is the whole reason
only mosaic has sub-families", which no longer follows now that a sub-family is reached by a
predicate. Tile stops being "one member of a family's unit space". A new Lattice
address term is added.

The spike section. The README's Unit Spaces Beyond Mosaic spike closes with four follow-up
bullets for "if the decision is ever revisited". The fourth — "give the space a canonical
identifier and a symmetry folding" — is now implemented, and the other three are not. The section
records which, and records that its recommendation to leave the asymmetry stands for the
reason it was given: that verdict was about materializing a space holding twelve million tiles at
five rows, and addressing one point of a space requires no materialization.

An architecture decision record for addressing meanders by their lattice rather than by their
family — why a snake has a hexadecimal name, why the identifier left the mosaic module, and why
the address is literal with the canonical class reported beside it rather than substituted for
it.

Acceptance criteria

• The glossary's Unit space entry keeps the enumerability claim and drops the sub-family
  inference
• The glossary's Tile entry no longer scopes a tile to one family's unit space
• Lattice address is defined in the glossary
• The spike section names which of its four follow-up bullets is implemented and restates why
  its recommendation is unaffected
• An architecture decision record covers the lattice address, the module move, and the
  literal-versus-canonical choice
• Spell check and markdown lint pass on every edited document

Blocked by

• feat(meanderaw): ✨ commit the lattice address table behind a check target #675, so the documents describe what actually shipped.