docs: index ADRs and plans, wire into SUMMARY.md

docs/README.md

@@ -15,8 +15,8 @@ Start here if you're considering a feature contribution or want to understand Ja
 - **[Timing Correctness](timing-correctness.md)**: Scoped requirements for timing accuracy, validation, and the forthcoming timing IR.
 - **[Timing Model Extensions](timing-model-extensions.md)**: Pre-spike design notes for δ(T) dynamic delay, clock-tree skew, and wire delay at scale. Formalised in ADR 0007.
 - **[Post-Phase-0 Roadmap](plans/post-phase-0-roadmap.md)**: Sequencing of Phase 1+ work covering structured timing output (ADR 0008) and timing model fidelity (ADR 0007). (OpenTimer integration was originally Phase 1's centrepiece; ADR 0003 was Superseded by the spike — OpenSTA out of process is now the sole STA path per ADR 0001.)
-- **[Architecture Decision Records](adr/)**: Design decisions and their rationale (numbered, per-decision).
-- **[Implementation Plans](plans/)**: Phased implementation plans with entry and exit criteria.
+- **[Architecture Decision Records](adr/README.md)**: Design decisions and their rationale (numbered, per-decision). See the index for status and how the ADRs relate.
+- **[Implementation Plans](plans/README.md)**: Phased implementation plans with entry and exit criteria. See the index for status and reading order.
 - **[Spikes](spikes/)**: Time-boxed experiments and their outcomes.
 
 ### Core Documentation

docs/SUMMARY.md

@@ -10,3 +10,24 @@
 - [Adding a New PDK](adding-a-pdk.md)
 - [Troubleshooting VCD](troubleshooting-vcd.md)
 - [Handoff Discipline](handoff-discipline.md)
+
+# Decisions & plans
+
+- [Architecture Decision Records](adr/README.md)
+  - [0001 — OpenSTA as the timing correctness oracle](adr/0001-opensta-as-oracle.md)
+  - [0002 — Timing intermediate representation](adr/0002-timing-ir.md)
+  - [0003 — OpenTimer as in-process reference STA (Superseded)](adr/0003-opentimer-primary-sta.md)
+  - [0004 — Private PDK testing track](adr/0004-private-pdk-testing.md)
+  - [0005 — OpenSTA vendoring and test-corpus strategy](adr/0005-opensta-vendoring-and-corpus.md)
+  - [0006 — SDF preprocessing model](adr/0006-sdf-preprocessing-model.md)
+  - [0007 — Timing model fidelity roadmap (Proposed)](adr/0007-timing-model-fidelity-roadmap.md)
+  - [0008 — Structured timing output as first-class deliverable](adr/0008-structured-timing-output.md)
+- [Implementation Plans](plans/README.md)
+  - [Post-Phase-0 Roadmap](plans/post-phase-0-roadmap.md)
+  - [GF180MCU PDK enablement](plans/gf180mcu-enablement.md)
+  - [Phase 0: Timing IR and OpenSTA oracle](plans/phase-0-ir-and-oracle.md)
+  - [WS2: opensta-to-ir](plans/ws2-opensta-to-ir.md)
+  - [WS3: delete SDF parser](plans/ws3-delete-sdf-parser.md)
+  - [WS3 follow-up: cosim --sdf](plans/ws3-cosim-sdf-followup.md)
+  - [Multi-clock and stimulus architecture](plans/multi-clock-and-stimulus-architecture.md)
+- [Spike — OpenTimer on SKY130](spikes/opentimer-sky130.md)

docs/adr/README.md

@@ -0,0 +1,54 @@
+# Architecture Decision Records
+
+ADRs capture decisions worth understanding later: the context, the
+options considered, and the rationale for the choice. They are
+numbered, append-only, and never silently rewritten — if a decision
+changes, supersede the old ADR with a new one and update the status.
+
+## Status legend
+
+- **Accepted / Approved** — current, in effect.
+- **Proposed** — drafted, not yet ratified.
+- **Superseded** — historical, replaced by a later ADR or by a spike
+  outcome; kept for the audit trail.
+
+## Index
+
+| # | Title | Status |
+|---|---|---|
+| [0001](0001-opensta-as-oracle.md) | OpenSTA as the timing correctness oracle and sole STA path | Accepted (scope expanded 2026-05-01) |
+| [0002](0002-timing-ir.md) | Timing intermediate representation | Accepted |
+| [0003](0003-opentimer-primary-sta.md) | OpenTimer as in-process reference STA | Superseded (2026-05-01) — spike failed; OpenSTA subprocess only |
+| [0004](0004-private-pdk-testing.md) | Private PDK testing track | Accepted |
+| [0005](0005-opensta-vendoring-and-corpus.md) | OpenSTA vendoring and test-corpus strategy | Accepted |
+| [0006](0006-sdf-preprocessing-model.md) | SDF preprocessing model and interim-to-release cutover | Accepted (amended 2026-05-02) |
+| [0007](0007-timing-model-fidelity-roadmap.md) | Timing model fidelity roadmap | Proposed |
+| [0008](0008-structured-timing-output.md) | Structured timing output as first-class deliverable | Approved |
+
+## How the ADRs relate
+
+- **0001 / 0003 / 0005 / 0006** describe the timing oracle stack:
+  OpenSTA as the ground truth (0001), vendored at a pinned revision
+  with its own corpus reused (0005), driving SDF preprocessing
+  out-of-process (0006). The earlier OpenTimer in-process plan (0003)
+  was retired after the spike ([`../spikes/opentimer-sky130.md`](../spikes/opentimer-sky130.md)).
+- **0002** is the data contract those tools talk over — a JSON timing
+  IR consumed by Jacquard, produced by `opensta-to-ir`.
+- **0004** governs how PDK-specific testing happens for NDA-bound
+  contributors without leaking files into the public repo.
+- **0007 / 0008** are the forward-looking pair: 0008 (Approved)
+  defines the structured timing output Jacquard owes downstream
+  flows; 0007 (Proposed) sketches the model-fidelity work needed to
+  back those outputs at scale (δ(T), clock-tree skew, wire delay).
+  Scheduling for both lives in
+  [`../plans/post-phase-0-roadmap.md`](../plans/post-phase-0-roadmap.md).
+
+## Adding a new ADR
+
+1. Pick the next number (highest existing + 1).
+2. Filename: `NNNN-short-kebab-title.md`.
+3. Start with `# ADR NNNN — <title>` and a `**Status:**` line.
+4. Standard sections: Context, Decision, Consequences. Add Amendment
+   blocks dated when the decision is revisited; do not rewrite
+   accepted history.
+5. Add the row to the table above.

docs/plans/README.md

@@ -0,0 +1,55 @@
+# Implementation Plans
+
+Phased implementation plans with entry and exit criteria. Plans live
+here when the work spans multiple commits and needs an explicit
+scheduling artefact; once shipped, the plan is kept as a historical
+record (Status flipped to *Implemented*) rather than deleted, so the
+phasing is recoverable later.
+
+For short-lived working memory between sessions, see
+[`../handoff-discipline.md`](../handoff-discipline.md) — that lives
+in `docs/handoffs/` and is deliberately kept separate from the
+persistent plans here.
+
+## Status legend
+
+- **Active** — currently being worked on or scheduled.
+- **Implemented** — shipped; kept as historical record.
+- **Deferred** — captured for future work; not currently scheduled.
+- **Exploratory** — architectural thinking captured ahead of demand.
+
+## Index
+
+| Plan | Status |
+|---|---|
+| [Post-Phase-0 Roadmap](post-phase-0-roadmap.md) | Active — scheduling doc for ADRs 0007 and 0008 |
+| [GF180MCU PDK enablement](gf180mcu-enablement.md) | Mostly implemented — Phases 0–6 shipped; Phase 7 deferred |
+| [Phase 0: Timing IR and OpenSTA oracle](phase-0-ir-and-oracle.md) | Implemented — historical record |
+| [WS2: `opensta-to-ir`](ws2-opensta-to-ir.md) | Implemented — historical record |
+| [WS3: delete SDF parser + interim runtime hook](ws3-delete-sdf-parser.md) | Implemented — historical record (see ADR 0006 Amendment) |
+| [WS3 follow-up: re-add cosim `--sdf` via `opensta-to-ir`](ws3-cosim-sdf-followup.md) | Deferred |
+| [Multi-clock and stimulus architecture](multi-clock-and-stimulus-architecture.md) | Exploratory — demand-driven |
+
+## Reading order for new contributors
+
+If you want to understand how the timing stack got to where it is:
+
+1. [`phase-0-ir-and-oracle.md`](phase-0-ir-and-oracle.md) — the
+   umbrella plan, with the five work streams (WS1–WS5).
+2. [`ws2-opensta-to-ir.md`](ws2-opensta-to-ir.md) and
+   [`ws3-delete-sdf-parser.md`](ws3-delete-sdf-parser.md) — the
+   per-work-stream detail for the IR producer and the SDF parser
+   removal.
+3. [`post-phase-0-roadmap.md`](post-phase-0-roadmap.md) — what comes
+   next, sequenced against the ADRs.
+
+## Adding a new plan
+
+1. Filename: short kebab-case (`<topic>.md` or
+   `<ws-or-phase>-<topic>.md`).
+2. Start with `# Plan — <title>` and a `**Status:**` line.
+3. Where the plan executes a specific ADR or work stream, name them
+   in a `**Predecessors:**` / `**ADRs:**` block near the top so the
+   dependency graph is explicit.
+4. Add the row to the table above. When the plan ships, change the
+   status in the file and here in the same commit.