FE-1089: Sync planning docs at orchestrator-cutover close

[kostandinang]

Stack Context

Final PR of the executor cutover stack (#274 → #282). It updates only the planning documents to match what the stack actually built. No product behavior changes — #282 below it stays a pure feature diff.

What?

• memory/SPEC.md — the spec still described real execution as "inactive until the real-execution stack lands". That stack has now landed, so the executor decision (D101-L) and invariant (I56-L) are rewritten to describe reality: all execute_* tools are active in CODE mode, real git/subprocess/agent work enters only through the injected ExecutionPorts, and host changes are file-only behind an accepted commit SHA. Five per-PR implementation notes were collapsed into a pointer to src/executor/TOPOLOGY.md, which owns that detail. Also adds an ExecutionPorts glossary entry and names a known gap: the agent-runner tests prove wiring, not real-model output quality.
• memory/PLAN.md — marks the orchestrator-cutover arc done, moves the six finished work-item definitions to docs/archive/PLAN_HISTORY.md, and records that FE-1116 (FE-1116: Session-local elicitation gaps from a graph-derived seed #280) and FE-1115 (Add standalone .pi/components preview harness #281) are in flight on parallel branches, so their own PLAN/SPEC edits stay authoritative when merges meet.
• memory/cards/ — deletes 11 scope cards whose work is finished.
• Two small ride-alongs, both doc-shaped: refreshed ownership text in src/executor/TOPOLOGY.md, and a code comment in active-tools.ts that cited the wrong invariant id (I52-L → I56-L).

Why?

The planning docs lagged the code: they described the executor as mostly inactive and listed six finished work items as live. Syncing them now gives the next piece of work (executor observability) accurate docs to plan against, and keeping the cleanup out of #282 keeps that PR reviewable on its own.

Verification

npm run verify — 1156 tests passed / 1 skipped; build and markdown-link checks green.

[cursor]

PR Summary

Low Risk
Documentation and card cleanup only; no product logic changes beyond comment/topology text.

Overview
Closes the orchestrator-cutover arc in canonical planning docs after the FE-1089→FE-1118 stack, without changing executor runtime behavior.

memory/PLAN.md marks both prior arcs done, trims sequencing (FE-1116 in flight, stack in review), collapses recently completed entries, and replaces long live Frontier Definitions with pointers to docs/archive/PLAN_HISTORY.md. The 2026-07-02 archive section adds the full retired orchestrator and elicitor frontier blocks plus a register-numbering drift note (D99-L/I52-L vs live D101-L/I56-L).

memory/SPEC.md updates D101-L and I56-L to describe the landed injected-ExecutionPorts stack (including host promotion), thins the five D101-L port refinement blockquotes to topology pointers, adds an ExecutionPorts glossary row, requirement 26’s execute_* wording, and a real-provider worker quality blind spot.

Removes 11 exhausted memory/cards/ scope files from the cutover arc. Minor doc-only touches: src/executor/TOPOLOGY.md ownership/boundary wording and an I52-L→I56-L comment in active-tools.ts.

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[kostandinang]

Warning

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• FE-1089: Sync planning docs at orchestrator-cutover close #284 👈 (View in Graphite)
• FE-1118: Reconcile host executor promotion #282 : 1 other dependent PR (#285 )
• FE-1112: Reconcile run-local executor promotion #279
• FE-1111: Reconcile executor agent runner #278
• FE-1109: Reconcile executor sandbox worktrees and test runner ports #275
• FE-1089: Reconcile executor with alpha branch #274
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