docs: restructure docs and enforce 2.0 conventions

[Tcode-Motion]

This pull request addresses the total restructuring and validation of the TechScript documentation site.

Actions Performed

1. Auditing & Re-Mapping:

   • The flat docs/ folder had documentation spanning 20+ features mixed at the root level.
   • We executed an organizational remap into the correct categories: language/, compiler/, specification/, tooling/, guides/, reference/, and getting-started/.
   • Updated mkdocs.yml's nav object so that generated sites map correctly.

2. Source of Truth Adjustments:

   • TechScript recently locked into LANGUAGE_FREEZE_2.0.md which declared changes like model dropping in favor of class.
   • Updated docs/language/types.md to properly reference class instead of class / model.
   • Pulled the true, frozen engineering grammar definition into docs/specification/grammar.md.
   • Moved and pulled the true engineering spec text into the public language-specification.md.

3. Accuracy Check:

   • We ran cargo test --workspace and python3 verify_all_examples.py against the examples to ensure the existing syntax documented and run against TechScript still behaves normally despite our changes.

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PR created automatically by Jules for task 1513274867050769885 started by @Tcode-Motion

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