docs: reconcile requirements tracking with verified code state

Audit of all 35 [ ] items vs source found ~46% mis-marked. Add a
[/] partial marker; promote 7 shipped-but-open items to [x]
(S1/S4/S5/I1a/I3/I4/C1) and 9 substantially-built ones to [/]
with gap notes (S3/A1/V1/V2/V5/T3/H3/DOC1/X1). Fix CLAUDE.md's
false "Tier 4 is wired" claim — no PTY tests exist.

CLAUDE.md

@@ -73,8 +73,11 @@ Current decisions at a glance (each backed by an ADR):
 - **Sharing:** `export` command produces a zip without the `.db`;
   no hosted publishing (ADR-0007).
 - **Testing:** four-tier strategy from `cargo test` units up to
-  PTY-based end-to-end (ADR-0008). Tiers 1–3 are active; Tier 4
-  is wired only for the listed critical flows.
+  PTY-based end-to-end (ADR-0008). Tiers 1–3 are active; **Tier 4
+  is not yet wired** — ADR-0008 specifies the PTY harness and the
+  four critical flows, but no PTY deps or tests exist yet
+  (verified 2026-06-07; corrects an earlier "wired only for the
+  listed critical flows" claim). Tracked as `requirements.md` TT4.
 - **DSL syntax conventions:** required clauses use keyword
   grammar (`with pk`, `to table` optional, `from..to`, `set`,
   `where`); `--` flags are reserved for opt-in choices; one