docs(thesis): rewrite FFL scoping to the shipped relative model

[rlemke]

Recast Chapter 4 and all four addendums from the old flat container model to the relative $-scoping the compiler now ships.

Chapter 4 (thesis.md)

• §4.2/§4.3 — $ = immediate container; $$/$$$ walk up one lexical level each; steps in other blocks are never nameable.
• §4.3.2 (new) — nested blocks + up-level operators, anchored on the real migrated ExtractPlacesAcrossSubregions fanout and the o1/o2/o3 shadowing case that forces $$$ (REF_DOLLAR_OVERFLOW at $$$$); adds the facet-typed-parameter decomposition idiom as the anti-pyramid pattern.
• §4.5.1 — fix the step-level-block example: container is the step itself ($.a, never g.a); the caller is reached with $$.
• §4.6 — fix the stale catch example: $ is the caught step, exposing synthetic $.error_type/$.error; workflow inputs via $$.

Every FFL snippet was validated against the live compiler (relative scoping default-on).

Addendums

• ai-authorship.md — AI authored the redesign end-to-end; the parked $$-contract data point.
• defense.md — corrected Q8's stale prediction; added Q8a (up-levels + parked caller-contract) and Q8b (decomposition idiom + live flag-gated migration).
• future-thoughts-ai-native.md — terse-$ operators as a machine-oriented-notation data point; §9 centerpiece on AI-authored language + migration + deployment.
• future-thoughts-positioning-dissent.md — new §7 partitioning the optimistic claim.

PDFs regenerated.

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request updates several thesis chapters to document the transition of FFL's scoping model from a flat container scheme to a relative scoping model using $, $$, and $$$ operators. The updates cover the design rationale, nested block resolution, live migration strategy, and the balance between AI-driven terseness and human legibility. The feedback suggests correcting "dual-modeled" to "dual-modelled" in future-thoughts-positioning-dissent.md to maintain consistent UK spelling throughout the thesis.

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[gemini-code-assist]

The spelling "dual-modeled" uses the US convention. To maintain consistency with the UK spelling style used throughout the rest of the thesis (e.g., "modelling", "apologised", "serialised", "favour", "generalisation"), this should be changed to "dual-modelled".

Suggested change

Finally, the episode is a corrective to the "just let the agent rewrite it" gloss. The migration did not land as a big-bang replacement. It shipped flag-gated behind a dual model, backward-compatible — the new runtime still runs old FFL — with layered verification at each stage and a live rollout across the fleet rather than an in-place swap. That is competent, ordinary engineering discipline: compatibility windows, staged rollout, a rollback path. It is also exactly the discipline that the optimistic phrase elides. The agent's fluency at *writing* the redesign is real; what made the redesign *safe to deploy* was the same set of practices any careful team would have insisted on, and none of them were made unnecessary by the fact that an agent produced the diff. The headline ("an agent redesigned the language and shipped it") is true. The subtext ("and it was safe because it was dual-modeled, compat-preserving, staged, and reversible") is where the actual assurance lives — and that subtext is human-invariant.

The subtext ("and it was safe because it was dual-modelled, compat-preserving, staged, and reversible") is where the actual assurance lives — and that subtext is human-invariant.