Migrated from Method backlog

This issue was created from a legacy filesystem backlog card. GitHub Issues are now the live work tracker; repository docs remain Method evidence.

Source backlog: docs/method/backlog/up-next/PLATFORM_strand-and-support-intent-paths.md
Original lane: up-next
Original legend: PLATFORM

Original backlog card

Strand and support Intent paths

Status: planned implementation slice.

Depends on:

• Topology mutation Intent boundary audit
• Security/capabilities for fork/rewind/merge

Why now

Strands and support pins are topology-changing. They affect the causal geometry
that later reads, settlement, and braids observe. External callers should not
create strands or support geometry through direct service mutation calls.

Goal

Add narrow Intent-level external paths for creating a contract/runtime strand
from an explicit basis and for pinning/unpinning support when that is exposed to
application flows.

Likely files touched

• crates/echo-wasm-abi/src/kernel_port.rs
• crates/warp-core/src/strand.rs
• crates/warp-core/src/coordinator.rs
• crates/warp-core/src/cmd.rs
• crates/warp-wasm/src/warp_kernel.rs
• crates/warp-core/tests/strand_contract_tests.rs

Acceptance criteria

• Create-strand/fork external path is an EINT Intent against an explicit parent
  coordinate.
• Support pin and unpin external paths are EINT Intents when exposed outside
  the runtime.
• Direct registry/service calls remain internal implementation details.
• Stale basis, missing capability, missing provenance, duplicate strand, and
  invalid support geometry return typed obstruction/conflict posture.
• Successful operations emit tick/receipt evidence.

Non-goals

• Do not implement full braid settlement here.
• Do not add editor-specific strand nouns.
• Do not delete internal StrandRegistry or ProvenanceService APIs.

Test expectations

• Creating a strand through the Intent path records causal evidence.
• Direct external mutation is not required by tests.
• Stale or missing basis does not silently create a strand.
• Support pin/unpin requires an Intent path when used externally.