feat(graph): add full_verify preset — one-command build->spec->test->review

[alpibrupa]

Summary

• The chaining mechanism already existed generically via `from_spec` (`--pipeline=build,spec,test,review` already worked) — what was missing was a dedicated, memorable preset for exactly this sequence, matching Promote the build->spec->test->review graph.lex pipeline to one-command 'full verify' #120's own title.
• The closest existing preset, `impl_then_spec_then_test`, runs test and review in parallel after spec, so review sees the same untested output test is concurrently checking rather than reviewing what test verified.
• Adds `full_verify()` = build → spec → test → review as a strict sequence, wired into `preset()`/`preset_names()`/`preset_shape()`/`is_preset()`. Extended `spec_matches_preset()` to assert `build,spec,test,review` and `full_verify` produce identical shapes, matching the existing discipline for the other three presets.

Fixes #120

Test plan

• `lex check`/`lex fmt --check` — ok
• Full repo sweep — all pass
• `lex test` — 4/4 passed
• `lex doc-sync --check` — current
• Live end-to-end verification with `run_graph_persistent` against a real task ("implement fn double"): spec genuinely located and read the file build wrote (via glob/read tool calls), wrote and proved 4 real spec properties via `lex_spec_check` (self-correcting two real syntax mistakes along the way), test recognized the existing `examples{}` coverage instead of duplicating it, and review used `effects_of`/`attestation_query`/`lex_check` for a real, evidence-based verdict — confirmed this is genuine chaining, not four independent runs sharing a task description.
• Persistent trail inspection: all four `.lex/sessions/{impl,spec,test,review}.db` trails exist with distinct, mode-appropriate event counts — spec's alone has 4 real `verified.spec_check` attestations (matching the 4 proved properties) and 2 `cap.failed` events (matching the two self-corrected mistakes); test and review each have their own `verified.type_check`.

🤖 Generated with Claude Code