v0.9 sub-issue #7: Built-in echo Provider + end-to-end conformance harness + Quickstart docs

[devin-ai-integration]

v0.9 Sub-issue #7 — Built-in echo Provider + end-to-end conformance harness + docs

Part of v0.9 epic. Final sub-issue.

Pulls Stages 1–5 together: ships a built-in text_chat echo Provider so
the runtime can actually respond, adds the end-to-end conformance test
harness exercised in CI, and ships the v0.9 quickstart docs.

Spec ref

• docs/LIFE_RUNTIME_STANDARD.md Part B §B.2.1 (LifeCapabilityProvider)
• All sub-issues 1–6 above (this PR consumes their public surfaces).

Built-in echo Provider

runtime/providers/echo.py:

• Implements LifeCapabilityProvider for capability_name() == "text_chat".
• provider_name() == "echo-builtin", provider_version() == "1.0.0".
• sandbox_class() == "built_in".
• initialize(asset_paths, params, hard_constraints):
  • Reads params.system_prompt (if present) — used to prefix invoke().
  • Reads hard_constraints.max_response_length — clips output.
  • Stores both for invoke().
• invoke({user_input, hosted_api_allowed, ...}):
  • Returns {text: f"You said: {user_input}"} (no LLM).
  • Truncates to max_response_length if set.
  • Ignores hosted_api_allowed (the echo Provider has no hosted mode).
• teardown(): no-op.

This Provider is purely a reference implementation. It exists so a
fresh DLRS user can run lifectl run minimal-life-package.life and get
a meaningful response without installing any user-installed Provider.

Real Providers (TTS, video synthesis, GraphRAG-backed chat, ...) ship as
separate v0.10+ work via the DLRS Extension Architecture plugin system.

The echo Provider is auto-registered at runtime/providers/__init__.py
import time, ensuring ProviderRegistry finds it without explicit
configuration.

Update minimal-life-package fixture

examples/minimal-life-package/ already exists from v0.7 (#83) but
predates the v0.8 binding spec. Update the fixture so it has a
binding/runtime_binding.json declaring:

{
  "capabilities": ["text_chat"],
  "capability_binding": {
    "text_chat": {
      "asset_paths": [],
      "params": {
        "system_prompt": "You are a digital life instance of the test author."
      },
      "hard_constraints": {
        "max_response_length": 200
      },
      "engine_compatibility": [
        { "engine": { "name": "echo-builtin", "version_range": ">=1.0.0,<2.0.0", "strict": false } }
      ],
      "tier_floor": null
    }
  },
  "surface": {
    "ui_hints": {
      "disclosure_label": "(AI digital life instance of the test author)"
    }
  },
  "hosted_api_preference": {
    "allowed": false
  }
}

Mirror this update in the existing tools/build_life_package.py test
fixture path. Bump examples/minimal-life-package/manifest.json if
needed for v0.8 conformance.

End-to-end conformance harness

tools/test_runtime_conformance.py:

def test_e2e_minimal_life_package():
    # 1. Build the .life via existing builder
    pkg_path = build_minimal_life_package(tmpdir)
    
    # 2. Spawn lifectl run --once with a canned prompt
    proc = subprocess.run(
        ["lifectl", "run", "--once", "--no-tty",
         "--poll-interval-override", "1",
         pkg_path],
        input="Hello!\n",
        capture_output=True,
        timeout=30,
    )
    
    # 3. Assert stdout has the disclosure label + echo response
    assert proc.returncode == 0
    assert "(AI digital life instance of the test author)" in proc.stdout
    assert "You said: Hello!" in proc.stdout
    
    # 4. Assert audit log has all required events in the right order
    log = read_runtime_audit_log(pkg_path)
    assert event_order(log) == [
        "mount_attempted",
        "withdrawal_poll",          # pre-flight
        "capability_bound",         # text_chat → echo-builtin
        "mount_succeeded",
        "turn_started",
        "turn_completed",
        "withdrawal_poll",          # at least one watcher poll within 1s
        "unmount",
    ]
    
    # 5. Assert hash chain integrity
    assert validate_hash_chain(log)
    
    # 6. Assert no zombie subprocess
    assert no_zombie_children()


def test_e2e_withdrawal_revocation():
    pkg_path = build_minimal_life_package(tmpdir, withdrawal_url=mock_endpoint("/revoked"))
    # mock_endpoint returns {revoked: true} after 2 polls
    proc = subprocess.run(
        ["lifectl", "run", "--no-tty",
         "--poll-interval-override", "1",
         pkg_path],
        input="hi\nhi\nhi\nhi\nhi\n",
        capture_output=True,
        timeout=30,
    )
    assert proc.returncode == 0
    log = read_runtime_audit_log(pkg_path)
    assert any(e["event_type"] == "unmount" and e["reason"] == "withdrawal" for e in log)

5 conformance test cases total:

1. End-to-end happy path (above).
2. Withdrawal revocation triggers unmount within 2 polls.
3. Expiry triggers unmount.
4. Forbidden_use rejection round-trips.
5. Audit chain integrity across full session.

CI integration

.github/workflows/validate.yml: replace the per-stage runtime-*
jobs (added by sub-issues 1–6) with a single consolidated
runtime-conformance job that runs python tools/test_runtime_conformance.py

• all per-stage tests. Or keep both layers — final structure is up to
  the reviewer; either is acceptable.

Documentation

docs/LIFE_RUNTIME_QUICKSTART.md (new)

Walk-through:

1. Install the runtime (pip install -e . from repo root for now;
   pip install dlrs-runtime from PyPI is post-v0.9).
2. Build the example .life:
   python tools/build_life_package.py --record examples/minimal-life-package/.
3. Run it: lifectl run --once examples/minimal-life-package/out/*.life.
4. Inspect the runtime audit log:
   cat ~/.local/share/dlrs/mounts/<package_id>/events.jsonl.
5. What each Stage does (link to docs/LIFE_RUNTIME_STANDARD.md Part B).

README.md + README.en.md updates

Add a "Quickstart" section pointing at the runtime quickstart doc;
update the implementation-status badge from "spec only" to "reference
runtime ✓".

docs/IMPLEMENTATION_STATUS.md + docs/GAP_ANALYSIS.md

Mark v0.9 deliverables complete + flip the runtime-completeness from 0%
to ~30% (single .life only; multi-life / .world / plugins still pending).

CHANGELOG.md

Add v0.9.0 entry summarizing the 7 sub-issues + naming the milestone
v0.9-runtime-impl.

ROADMAP.md

Update the .life Runtime Standard track row for life-runtime v0.1.1
to mark "reference impl shipped (v0.9 epic)". Add a v0.10 placeholder row
referencing the embodiment + multi-life + DLRS-EA design.

Acceptance

• Echo Provider implements LifeCapabilityProvider correctly
• minimal-life-package binding updated to v0.8 spec
• All 5 e2e conformance test cases pass in CI
• Quickstart doc written + linked from README
• CHANGELOG / ROADMAP / IMPLEMENTATION_STATUS / GAP_ANALYSIS refreshed
• CI runtime-conformance job green
• Tag v0.9-runtime-impl ready for release

After merge, the v0.9 epic closes; v0.10 epic kicks off.