docs(board): debt remediation plan 2026-06-09 (P0 / fruit / structure)

Roadmap companion to DEBT_REVIEW_2026-06-09.md + the TD rows. Folds in
the user's hard constraints (no autofix; no deletion of unused code/deps
without per-item confirmation — sharpened by the P0 AdaWorldAPI-fork
policy for lance/lancedb/ndarray-family deps; scoped Sonnet agents +
review gates).

lance-graph is the HEALTHY repo: workspace clippy GREEN, member unsafe
hygiene sound, heavy unsafe quarantined in excluded holograph. So the
only P0 is trivial (C3: protobuf-compiler in CI). Low-hanging fruit =
ontology-12 sweep. Wave plan W0–W2 + a propose-and-confirm queue for the
machete member-dep findings (prost flagged as a feature-gated false
positive). TD-DEEPNSM-CLIPPY-195 noted resolved in #479.

https://claude.ai/code/session_01KQGUNH5N5Lg4Pb9WduLnqQ

Author: claude

.claude/board/DEBT_REMEDIATION_PLAN_2026-06-09.md

@@ -0,0 +1,107 @@
+# Debt Remediation Plan — 2026-06-09 (lance-graph)
+
+> **Companion to** `DEBT_REVIEW_2026-06-09.md` (the findings) and the TD rows
+> `TD-UNUSED-DEPS-MACHETE-2026-06`, `TD-CLIPPY-ONTOLOGY-12`,
+> `TD-ENV-PROTOC-MISSING` in `TECH_DEBT.md`.
+> **Branch:** `claude/quirky-volta-m2r6ak` (rebased onto post-#479 main `4d26776`).
+> **Cross-repo twin:** `ndarray/.claude/board/DEBT_REMEDIATION_PLAN_2026-06-09.md`.
+
+## Hard execution constraints (non-negotiable — set by the user 2026-06-09)
+
+1. **No autofix.** No `cargo clippy --fix` (it mangled `reader_state.rs` in
+   #479). Work via **tightly-scoped Sonnet agents that reason and write**.
+2. **No deletion of unused code or dependencies — ever — without explicit
+   per-item confirmation.** All "unused" findings are a **propose-and-confirm
+   queue**, never an autonomous action list. **P0 fork policy makes this sharper:**
+   removing `lancedb`/`lance`/`ndarray`-family deps must NOT break AdaWorldAPI-fork
+   wiring — verify load-bearing-ness before a dep is even a candidate.
+3. **Every wave ends at a named review gate**, per
+   `.claude/rules/agent-cargo-hygiene.md` (fleet without worktrees, edit-only,
+   Opus orchestrator compiles + lints once).
+
+## State: lance-graph is the HEALTHY repo
+
+Unlike ndarray (suppression-masked, one RED), lance-graph's workspace clippy is
+**GREEN** (`cargo clippy --workspace --all-targets` exit 0, 53 warnings / ~38
+unique), and member unsafe hygiene is sound (35 `unsafe {` / 33 `// SAFETY:`;
+the heavy FFI unsafe is quarantined in the *excluded* `holograph`). So there is
+**no P0 clippy fire here** — the work is hygiene + keeping the quarantine honest.
+
+Of the 53 warnings, **~17 are intentional** `I-LEGACY-API-FEATURE-GATED` v2
+deprecation migrations (`CausalEdge64::inference_type()` / `set_temporal()`) —
+**LEAVE them**; they retire with the v2 layout migration.
+
+## P0 — Core (only one, and it's trivial)
+
+| # | Item | Why P0 | Effort | Owner / gate |
+|---|---|---|---|---|
+| **C3** | Add `protobuf-compiler` to CI image + dev bootstrap (`TD-ENV-PROTOC-MISSING`). | From clean, `cargo clippy --workspace`/`build` fails *"Could not find `protoc`"* (prost/tonic under the `lance` stack + lab `grpc` feature). Repro/CI fragility. | XS (CI YAML + docs) | CI |
+
+## Low-hanging fruit (additive/rewrite, scoped — no deletion)
+
+- **`lance-graph-ontology`: 12 lib clippy warnings** (`TD-CLIPPY-ONTOLOGY-12`) —
+  the one member cluster in an otherwise-GREEN workspace. Mostly
+  `needless_range_loop` + doc-indent; one scoped agent, rewrites not deletions.
+- **(Optional) `cognitive-shader-driver` 7 warnings** (`TD-CLIPPY-SHADER-DRIVER`,
+  already logged) — small, fold into the same sweep if convenient.
+
+## Leave alone / gate
+
+- **v2 deprecation warnings (~17)** — intentional migration. Leave.
+- **`TD-DEEPNSM-CLIPPY-195`** — **already RESOLVED in #479** (deepnsm clippy swept,
+  CI promoted advisory→gating). No action.
+- **`TD-BGZ-TENSOR-5-FAILURES-330`, `TD-FMT-STANDALONE-CRATES-4400`** — already
+  logged, excluded-crate scope, separate efforts.
+- **Unused deps** → **propose-and-confirm queue** (bottom). Nothing removed
+  without sign-off.
+
+## Structural fix (prevents recurrence)
+
+1. **Keep the excluded-crate quarantine honest.** The heavy unsafe + the
+   bulk of clippy debt lives in *excluded* crates (`holograph`,
+   `thinking-engine`, `deepnsm`, `bgz-tensor`). That's a deliberate boundary —
+   but when a crate graduates `exclude → members` (the Phase-3 plan does this for
+   `bgz17`), it MUST pass the member clippy gate first. Add that as a graduation
+   checklist item.
+2. **Unused-dep discipline under P0 fork policy.** Track in `TECH_DEBT.md`; remove
+   only on per-item sign-off; never let a removal silently drop fork wiring.
+3. **`protoc` is a documented prereq** (C3) — no more clean-env breakage.
+
+## Wave sequencing (lance-graph slice)
+
+| Wave | Scope | Agent(s) | Gate | Acceptance |
+|---|---|---|---|---|
+| **W0** | C3 (CI YAML + build-prereq docs) | CI/`integration-lead` | Opus `--workspace` lint w/ protoc | clean-env build/clippy succeeds |
+| **W1** | `lance-graph-ontology` 12-warning sweep (one scope) | Sonnet, `product-engineer`-style review | Opus `cargo clippy -p lance-graph-ontology` GREEN at `-D warnings` | rewrites only, tests green |
+| **W2** | Present the propose-and-confirm queue → act ONLY on confirmed items | (review) | **user sign-off per item** | nothing deleted without a tick |
+
+### Scoped-agent mission template (every wave)
+> Scope: ONE crate/file. Model: Sonnet. **Edit-only; no worktree; no
+> `cargo build`/`check`; NO `clippy --fix`; NO deletion of any dep or item.**
+> Read `DEBT_REVIEW_2026-06-09.md` + this plan + `AGENT_LOG.md` first; prepend an
+> `AGENT_LOG.md` entry on completion. Opus compiles + lints centrally.
+
+## Propose-and-confirm queue (lance-graph) — NOTHING removed without your sign-off
+
+**Member-crate unused deps (`cargo-machete`, verified on post-#479 tree):**
+
+| crate | candidate deps | note |
+|---|---|---|
+| `lance-graph` (core) | `bgz17`, `bgz-tensor`, `lancedb`, `datafusion-expr` | first 3 = **0 src refs**; `lancedb` removal is **P0-fork-sensitive** — verify first |
+| `lance-graph-planner` | `bgz17`, `p64`, `p64-bridge`, `serde`, `serde_yml` | |
+| `surreal_container` | `futures`, `lance`, `lancedb`, `snafu`, `tokio` | `lance`/`lancedb` fork-sensitive |
+| `lance-graph-callcenter` | `axum`, `tokio-tungstenite`, `tower-http` | |
+| `lance-graph-ontology` | `arrow-array`, `once_cell` | |
+| `lance-graph-catalog` | `snafu` | |
+| `lance-graph-archetype` | `lance-graph-contract` | |
+| `lance-graph-supervisor` | `lance-graph-callcenter`, `lance-graph-contract` | |
+
+⚠️ **Verified FALSE POSITIVE — keep:** `cognitive-shader-driver → prost`
+(`optional = true`, lab-only `grpc` feature). Triage rule: every machete hit
+needs a per-entry check; optional/feature-gated + `-src` deps are false positives.
+
+(Excluded crates also flagged — `osint` 8, `holograph` 8, `thinking-engine`
+`hf-hub`, `deepnsm` `ndarray`, `learning`/`cognitive` `contract` — lower
+priority, not CI-gated.)
+
+Cross-ref: `DEBT_REVIEW_2026-06-09.md`, `TECH_DEBT.md` (TD-UNUSED-DEPS-MACHETE-2026-06).