docs: 1.0 documentation restructure

Split root CLAUDE.md into 19 per-directory files scoped to their source area.
Roll v0 history into docs/ARCHIVE.md; retire CONTEXT.md, CONTEXT-ARCHIVE.md,
PLAN.md, COMPLETED.md. Move plan docs under docs/. Rescue 9 live deferrals
into docs/TODO.md.

docs/product/code-organization.md

@@ -9,8 +9,10 @@ subdirectories) **without sacrificing runtime performance**, against a stated qu
 >
 > Bring the codebase "**into the realm of something I can stand to look at.**"
 
-Its build roadmap lives in **PLAN.md §Phase Q** and its authoritative spec in
-**CONTEXT.md §Phase Q**. This doc holds the *why* — the quality bar, the evidence base
+Its build roadmap's landed history lives in **`docs/ARCHIVE.md`** ("Phase Q — Quality:
+the decision record") and its authoritative spec now lives in root **`CLAUDE.md`**
+(§Directory and namespace layout, §Performance guardrails, §Structural heuristics)
+plus the per-directory `src/**/CLAUDE.md` files. This doc holds the *why* — the quality bar, the evidence base
 (a grep-verified SOLID audit), the target directory/namespace shape grounded in the Vital
 reference, and the numbered fork decisions.
 
@@ -321,10 +323,10 @@ re-namespaced, and split, not carried forward untouched into a tidier tree. "Som
 look at" is partly shape (§2/§2b) and partly *functional soundness* (§2c).
 
 Q-W0 is **not executed by product-designer** — this doc *defines the wave and its scope*; the audit
-itself is staff-engineer/DSP work. The authoritative wave definition lives in **PLAN.md §Q-W0** and
-its spec framing in **CONTEXT.md §"The pre-restructure audit wave (Q-W0)"**; this section is the
-evidence-doc framing (the *why* and the smell taxonomy), matching how §2/§2b frame the structural
-audits.
+itself is staff-engineer/DSP work. The wave's landed history lives in **`docs/ARCHIVE.md`**
+("Q-W0 fix-now remediations" and "Phase Q — Quality: the decision record"), and its findings live in
+**`docs/product/code-quality-audit.md`**; this section is the evidence-doc framing (the *why* and
+the smell taxonomy), matching how §2/§2b frame the structural audits.
 
 ### 2c.1 Audit surfaces (the named targets)
 
@@ -451,7 +453,7 @@ namespace of every header, splitting the four largest TUs). Meanwhile:
 - **Phase L** has **L3** (VST editor + embed-strip restyle, gated on Phase S landing on dev)
   still to land — it touches the Phase S draw shells (`reasampler_editor` / `reasampler_embed`),
   which arrive on dev with Phase S. (L1/L2/L4/L5/L6/L7 have **already landed** — see
-  `COMPLETED.md`; the once-listed "L2 pending" is stale and has been corrected here.)
+  `docs/ARCHIVE.md`; the once-listed "L2 pending" is stale and has been corrected here.)
 - **D2** is **functionally complete** (D2-W1..W3-B landed; the only open item — a per-track
   lane-split panel indicator — is *explicitly deferred*, not a blocking residual). **M9** (slots)
   is **abandoned** (Daniel, 2026-07-27) — will not be built. D2 is named in the gate only so a