docs(habitat): add deep refactor implementation reference frame

[mateicanavra]

This PR adds an implementation reference frame document for the Deep Habitat Toolkit refactor, establishing the normative operating context for the directly responsible implementation agent executing the prepared packet suite.

The document defines:

• Operating posture and source authority hierarchy — clarifying that prior planning is complete, the current checkout is the implementation source of truth, and Habitat must remain a generic repo-local toolkit with host-specific policy entering only through a declared host policy boundary.
• Target domain model — a responsibility-first table of 16 domains (Command/API Contract through Execution Provenance Trigger) with explicit ownership boundaries and key inter-domain consumption relationships.
• Domino sequence — the full 17-step critical path from D0 (Scenario/Public Contract Inventory) through D15 (Execution Provenance Substrate Trigger), including where parallelism is permitted and what each step unlocks.
• Per-packet execution control questions and closure anchors — a table specifying the primary state reduction and the exact condition that must be true before each packet can claim closure.
• TypeScript discipline rules — requirements around discriminated states, type/runtime honesty, proportional complexity, and explicit rejection of generic mega-frameworks.
• Done criteria, review lanes, supervisor integration model, hard constraints, and stop conditions — including the specific watcher artifact and proof-risk conditions that require an immediate halt.
• Known current proof risks — test target failures, Nx daemon issues, Oclif flag inconsistencies, false-green colon-target parsing, and Graphite restack state that constrain proof claims during implementation.
• First execution step — D0 opens with repo isolation, dependency/build grounding, and public-surface inventory before any internal extraction begins.

[mateicanavra]

• docs(habitat): add D0 public contract inventory for deep refactor #1809
• docs(habitat): add deep refactor implementation reference frame #1808 👈 (View in Graphite)
• main

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