[TASK][PROGRAMME.T02] Bootstrap the Rust repository and contribution boundary

Parent: #1

Task ID: `PROGRAMME.T02`

## Implementation
Propose a Cargo workspace, pinned toolchain, minimal shell/supervisor/worker entrypoints, formatting/lint/test automation, architecture decision records and ownership files. Keep kernel research in its own build boundary and do not create dozens of empty crates before interfaces justify them.

## Deliverable
Repository bootstrap pull-request plan and developer setup.

## Verification
A clean environment can build and test the initial real modules with no private credentials or undocumented machine dependencies.

## Guardrail
Repository bootstrap remains proposed work; this issue-creation pass creates no code or PR.

## Prerequisites
- `PROGRAMME.T01`

Review: pending · Implementation: not started.

Start by reviewing prerequisite PROGRAMME.T01 and the parent issue, then define the proposed Cargo workspace and pinned toolchain boundary. The plan should cover the shell, supervisor, and worker entrypoints, formatting/lint/test automation, architecture decision records, and ownership files. Done means a clean environment can build and test the initial real modules without private credentials or undocumented dependencies.

Written by the indexing model from the issue text.