docs(roadmap): consolidate July-2026 research into the combined roadmap

[gnanirahulnutakki]

Consolidates the July-2026 market research (docs/research/MARKET-RESEARCH-2026-07.md, PR #45) and the just-landed specs (PRs #40–#43) into the roadmap doc, so docs/ROADMAP.md and the GitHub epic backlog tell one story.

What changed in docs/ROADMAP.md

• Phase L now lists the locked build-sequence slice table (Slices 0–6 + parallel P) mapped to issues Slice 0: Foundation walking-skeleton (repo, CLI, fleet.Source seam, green CI) #47/F2.1 (reshape): Source-abstract fleet model + local-kubeconfig source adapter #38/F11.1: Kubeconfig auto-detect + client-side fan-out #32/F11.2: Cache-first fleet render (CLI + TUI) #33/F11.5: Per-pod table stakes (logs / exec / port-forward / YAML) #35/F11.3: Local web "fleet IDE" (sith ui) #34/F11.6: No-account / no-telemetry / keychain custody #36/F7.1: MCP read tools (sith serve --mcp) #37/F14.5: Local advisory Investigation Brain (R1–R6 over reachable lenses) #48/E9: Deployment and packaging #27, plus the local advisory Investigation Brain and an egress-test exit criterion.
• New Investigation Brain (E14) section — deterministic, abstaining root-cause sequenced across Phase L (advisory) → P1 (four-lens graph) → P2/P3 (governed plan). Positions the 2026 AI-SRE wave as clients of Sith's governance, not competitors.
• New Integration waves (E12) section — W1–W4 with the daily-core coverage the six brain rules need.
• New Standards-alignment gates section — MCP 2026-07 auth + enforce-at-execution (CVE-2026-46519), OTel semconv keys, client-go ExecCredential v1, SLSA/cosign/SBOM, K8s API conventions.
• Anti-scope reaffirmed: no LLM in the root-cause critical path; no act-from-chat.

Companion GitHub backlog changes (this same pass)

• New epic E14: Investigation Brain (deterministic, rule-based, abstaining root-cause) #46 — E14 Investigation Brain; new Phase-L children Slice 0: Foundation walking-skeleton (repo, CLI, fleet.Source seam, green CI) #47 (Slice 0 foundation) and F14.5: Local advisory Investigation Brain (R1–R6 over reachable lenses) #48 (F14.5 local advisory brain).
• Refined epics E2: Read federation #20 E11: Local fleet client (the adoption wedge) #29 E12: Connector framework #30 E9: Deployment and packaging #27 E1: Tenancy and identity #19 E4: Action federation #22 E5: Policy federation and governance #23 E7: Governed MCP server #25 with research-backed acceptance criteria + labels (investigation-brain, standards-alignment, supply-chain, foundation).
• Spec/slice reference footers added to Phase-L children F2.1 (reshape): Source-abstract fleet model + local-kubeconfig source adapter #38 F11.1: Kubeconfig auto-detect + client-side fan-out #32 F11.2: Cache-first fleet render (CLI + TUI) #33 F11.5: Per-pod table stakes (logs / exec / port-forward / YAML) #35 F11.3: Local web "fleet IDE" (sith ui) #34 F11.6: No-account / no-telemetry / keychain custody #36 F7.1: MCP read tools (sith serve --mcp) #37.
• Roadmap tracking issue Sith implementation roadmap #39 updated to match.

Do not merge — review comes in a later step. Companion to the specs in PRs #40–#43 and research PR #45.