Release Open Pstack 1.15.0 without the Devin, agy and dsh repository refusals #216

Outcome

Open Pstack 1.15.0 ships the user-facing work merged since 1.14.0:

• PR refactor(runner): drop the Devin, agy and dsh repository refusals (#204) #215: Devin, agy and dsh lanes run in any repository; the runner no longer refuses .devin/, .agents/ and its siblings, or a cwd .env (runner: remove the Devin, agy and dsh repository refusals #204, under REVIEW.md: read-only means pstack's own CLI settings, with no refusals for the operator's setup #203).

Acceptance criteria

• One PR adds a ## 1.15.0 section to CHANGES.md, written from the body of PR refactor(runner): drop the Devin, agy and dsh repository refusals (#204) #215 and checked against main.
• The same PR bumps the version from 1.14.0 to 1.15.0 everywhere 1.14.0 appears as the current version: the marketplace manifest, both plugin manifests, the UPSTREAM.md table, README.md and docs/reference.md.
• The Cursor sync point does not change.
• The PR head passes verify, Unfret and its exact-head live-gate, run from trusted main with claude:hook:startup and codex:hook:startup; refactor(runner): drop the Devin, agy and dsh repository refusals (#204) #215's own live gate covered the runner.
• After merge, python3 scripts/release.py publish tags the live-gated head and publishes the v1.15.0 release.