docs: roadmap v0.8 → v0.11 + rivet SDLC artifacts

[avrabe]

Summary

Plans the residual work from the two open umbrellas (#94 P3 async,
#130 DWARF / witness MC/DC) across four minor releases and ties each
deliverable to a rivet requirement + traceability entry.

Release plan

Milestone	Issue	Rivet	Scope
v0.8.0	#140	SR-32	Stackful P3 lifting mode (#94 sub-C)
v0.9.0	#141	SR-33	Cross-component `stream` adapter (#94 sub-A)
v0.9.0 (stretch)	#142	SR-34	Static stream validation (#94 sub-B) — slips to v0.10 if #141 not in time
v0.10.0	#143	SR-35	DWARF Phase 2 — address remap (#130)
v0.11.0	#144	SR-36	DWARF Phase 3 — synthesised adapter DIEs (#130)

What lands in this PR

• `docs/roadmap.md` (148 lines) — human-facing living plan with rationale, cadence, and SDLC checklist.
• `safety/requirements/safety-requirements.yaml` — five new rivet artifacts SR-32..SR-36, each tagged `roadmap` with `status: planned` and linked to its tracking issue + dependency requirement.
• `safety/requirements/traceability.yaml` — `verification-status` placeholders for each new SR (`status: planned`, empty test/proof lists, populated as work lands).

Cadence change

Five releases in two weeks (v0.3 → v0.7) was faster than downstream consumers can absorb. Targeting ~one minor per 3–4 weeks going forward, batched thematically. Smithy reliability gate (#139) must clear before lifting `--admin`-merge precedent.

Cross-cutting tracks documented in the roadmap

• Smithy fleet reliability — rolling tracker (meld side) #139 smithy reliability acceptance bar
• Mythos delta passes per release (existing pattern)
• RFC fix: correct callee_defines_resource for sentinel type entries #46 alignment — two anticipated meld touchpoints from alexcrichton's 2026-04-08 comment (no injected memories, multi-module output mode)

SDLC definition of "release done"

The roadmap encodes a 6-step gate every release must pass:

1. All milestone issues closed
2. Their rivet requirements marked `status: implemented`
3. Their traceability entries point at real test files / proof paths
4. CHANGELOG `[Unreleased]` renamed to `[vX.Y.Z] — `
5. Pre-release Mythos scan completed; findings fixed or filed
6. Tag pushed; release.yml produced all 4 binaries

Same shape as v0.3 → v0.7 already followed, now written down.

Out of scope explicitly

• Variable-level DWARF (`.debug_loc`, `.debug_loclists`)
• `OutputFormat::MultiModule` (RFC fix: correct callee_defines_resource for sentinel type entries #46 alignment work — design exploration first)
• Runtime perf regression detection (WarpL deferred per docs/arxiv-2604.13693-warpl-evaluation.md)

Test plan

• Roadmap renders cleanly in GitHub markdown
• Five new SR entries pass any rivet schema validation in CI
• traceability.yaml is parseable as YAML
• Milestone references in issues match the created milestones