Workbench player click-to-seek, in-place Gherkin editor, and local-site demo

[ds-code-t]

Summary

Next Workbench player/editor increment on the 2.1.9 line. Swing stays a presentation adapter over WorkbenchServices / executeStep; worker-side DynamicControl / GherkinControl remain the only Gherkin interpreters.

Requested product behavior:

• Clicking a scenario line instantly seeks the playhead (audio-player needle). Global Play still starts from the first executable step in a fresh worker context.
• Step Editor has two play actions: Step (isolated executeStep, leaves playback paused) and From Here (fresh context, run from the selected/playhead step through the rest of the buffer).
• Reaching the end stays in play (WAITING_FOR_STEP). Enter appends a step to the live scenario and queues execution. The same happens when an executable line is typed at the end of the document while waiting.
• The Live Scenario Editor is an in-place Gherkin document. Previously executed lines remain editable. Stable line ids are preserved for same-index edits.
• New sessions load a Workbench-owned browser demo against URL.home and the Maven consumer local test site (navigate + click Forms Playground). The buffer is not written back to consumer .feature files.

Architecture:

• No second worker manager, Mapping implementation, or Pickleball runtime in Swing.
• Displayed Gherkin is sent unchanged. Keyword stripping stays in worker-side DynamicControl.
• Isolated and buffered execution both use the existing WorkbenchServices.executeStep seam already exposed to MCP as workbench_execute_step.
• No protocol, dependency, version, or resource-path RunVar changes.

CI wrapper mode fix

GitHub Actions failed before tests with ./gradlew: Permission denied because POSIX wrappers were committed as 100644. Restored execute bits only (same blobs):

• gradlew 100644 → 100755
• maven-consumer-project/mvnw 100644 → 100755
• scripts/agent_validate.sh 100644 → 100755

.github/workflows/agent-contract.yml now chmod +x immediately before invoking ./gradlew and ./maven-consumer-project/mvnw.

Functionality-change coverage

• I reviewed AGENTS.md and the relevant feature-map entry.
• Framework implementation is complete.
• Focused framework tests were added or updated.
• Maven consumer scenarios were not added. Existing @control-bridge already covers full-Gherkin Given ... normalization; this increment does not change that worker contract.
• Canonical Workbench docs, player guide, feature map, and repository index were updated.
• Backward compatibility was preserved. First/Step Back were already absent on 2.1.9; click-to-seek replaces that navigation.

Validation

• python3 scripts/verify_agent_contract.py
• python3 scripts/refresh_agent_index.py --check
• python3 scripts/sync_consumer_guidance.py --check
• bash ./gradlew :pickleball-workbench:test — BUILD SUCCESSFUL
• ./gradlew verifyStrictControllerIsolation — not run; protocol, artifacts, and Workbench dependencies were not changed
• @control-bridge / @step-override-bridge — not run; worker/DynamicControl/protocol contracts were not changed
• @all — not run (Workbench rule)
• Interactive Swing UI — cannot be exercised in this environment

Remaining manual UI checks

1. Click steps and confirm the playhead highlight seeks immediately.
2. Global Play starts from the first demo step even after seeking later.
3. Step vs From Here behave as documented.
4. Wait-at-end + Enter appends and continues.
5. Edit previously executed Gherkin in place.
6. Default demo navigates to the local test site and clicks Forms Playground once a worker is up.