feat(#370): install mosaicstack-telemetry in Coordinator

- Add mosaicstack-telemetry>=0.1.0 to pyproject.toml dependencies
- Configure Gitea PyPI registry via pip.conf (extra-index-url)
- Integrate TelemetryClient in FastAPI lifespan (start_async/stop_async)
- Store client on app.state.mosaic_telemetry for downstream access
- Create mosaic_telemetry.py helper module with:
  - get_telemetry_client(): retrieve client from app state
  - build_task_event(): construct TaskCompletionEvent with coordinator defaults
  - create_telemetry_config(): create config from MOSAIC_TELEMETRY_* env vars
- Add 28 unit tests covering config, helpers, disabled mode, and lifespan
- New module has 100% test coverage

Refs #370

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/coordinator/src/mosaic_telemetry.py

@@ -0,0 +1,157 @@
+"""Mosaic Stack telemetry integration for the Coordinator.
+
+This module provides helpers for tracking task completion events using the
+mosaicstack-telemetry SDK. It is separate from the OpenTelemetry distributed
+tracing configured in telemetry.py.
+
+Environment variables (auto-read by the SDK):
+    MOSAIC_TELEMETRY_ENABLED: Enable/disable telemetry (default: true)
+    MOSAIC_TELEMETRY_SERVER_URL: Telemetry server endpoint
+    MOSAIC_TELEMETRY_API_KEY: API key for authentication
+    MOSAIC_TELEMETRY_INSTANCE_ID: UUID identifying this coordinator instance
+"""
+
+from __future__ import annotations
+
+import logging
+from typing import TYPE_CHECKING
+
+from mosaicstack_telemetry import (
+    Complexity,
+    EventBuilder,
+    Harness,
+    Outcome,
+    Provider,
+    QualityGate,
+    TaskType,
+    TelemetryClient,
+    TelemetryConfig,
+)
+
+if TYPE_CHECKING:
+    from fastapi import FastAPI
+    from mosaicstack_telemetry import TaskCompletionEvent
+
+logger = logging.getLogger(__name__)
+
+
+def get_telemetry_client(app: FastAPI) -> TelemetryClient | None:
+    """Retrieve the Mosaic telemetry client from FastAPI app state.
+
+    Args:
+        app: The FastAPI application instance.
+
+    Returns:
+        The TelemetryClient if initialised and telemetry is enabled,
+        or None if telemetry is disabled or not yet initialised.
+    """
+    client: TelemetryClient | None = getattr(app.state, "mosaic_telemetry", None)
+    return client
+
+
+def build_task_event(
+    *,
+    instance_id: str,
+    task_type: TaskType = TaskType.IMPLEMENTATION,
+    complexity: Complexity = Complexity.MEDIUM,
+    outcome: Outcome = Outcome.SUCCESS,
+    duration_ms: int = 0,
+    model: str = "claude-sonnet-4-20250514",
+    provider: Provider = Provider.ANTHROPIC,
+    harness: Harness = Harness.CLAUDE_CODE,
+    estimated_input_tokens: int = 0,
+    estimated_output_tokens: int = 0,
+    actual_input_tokens: int = 0,
+    actual_output_tokens: int = 0,
+    estimated_cost_micros: int = 0,
+    actual_cost_micros: int = 0,
+    quality_passed: bool = False,
+    quality_gates_run: list[QualityGate] | None = None,
+    quality_gates_failed: list[QualityGate] | None = None,
+    context_compactions: int = 0,
+    context_rotations: int = 0,
+    context_utilization: float = 0.0,
+    retry_count: int = 0,
+    language: str | None = "typescript",
+) -> TaskCompletionEvent:
+    """Build a TaskCompletionEvent for a coordinator task.
+
+    Provides sensible defaults for the coordinator context (Claude Code harness,
+    Anthropic provider, TypeScript language).
+
+    Args:
+        instance_id: UUID identifying this coordinator instance.
+        task_type: The kind of task that was performed.
+        complexity: Complexity level of the task.
+        outcome: Whether the task succeeded, failed, etc.
+        duration_ms: Task duration in milliseconds.
+        model: The AI model used.
+        provider: The AI model provider.
+        harness: The coding harness used.
+        estimated_input_tokens: Estimated input token count.
+        estimated_output_tokens: Estimated output token count.
+        actual_input_tokens: Actual input token count.
+        actual_output_tokens: Actual output token count.
+        estimated_cost_micros: Estimated cost in USD micros.
+        actual_cost_micros: Actual cost in USD micros.
+        quality_passed: Whether all quality gates passed.
+        quality_gates_run: List of quality gates that were executed.
+        quality_gates_failed: List of quality gates that failed.
+        context_compactions: Number of context compactions during the task.
+        context_rotations: Number of context rotations during the task.
+        context_utilization: Final context window utilization (0.0-1.0).
+        retry_count: Number of retries before the task completed.
+        language: Primary programming language (default: typescript).
+
+    Returns:
+        A fully populated TaskCompletionEvent ready to be tracked.
+    """
+    builder = (
+        EventBuilder(instance_id=instance_id)
+        .task_type(task_type)
+        .complexity_level(complexity)
+        .harness_type(harness)
+        .model(model)
+        .provider(provider)
+        .duration_ms(duration_ms)
+        .outcome_value(outcome)
+        .tokens(
+            estimated_in=estimated_input_tokens,
+            estimated_out=estimated_output_tokens,
+            actual_in=actual_input_tokens,
+            actual_out=actual_output_tokens,
+        )
+        .cost(estimated=estimated_cost_micros, actual=actual_cost_micros)
+        .quality(
+            passed=quality_passed,
+            gates_run=quality_gates_run or [],
+            gates_failed=quality_gates_failed or [],
+        )
+        .context(
+            compactions=context_compactions,
+            rotations=context_rotations,
+            utilization=context_utilization,
+        )
+        .retry_count(retry_count)
+        .language(language)
+    )
+    return builder.build()
+
+
+def create_telemetry_config() -> TelemetryConfig:
+    """Create a TelemetryConfig instance.
+
+    The config reads from MOSAIC_TELEMETRY_* environment variables automatically.
+    Validation warnings are logged but do not prevent creation.
+
+    Returns:
+        A TelemetryConfig instance with env-var overrides applied.
+    """
+    config = TelemetryConfig()
+    errors = config.validate()
+    if errors and config.enabled:
+        logger.warning(
+            "Mosaic telemetry config has validation issues (telemetry may not submit): %s",
+            "; ".join(errors),
+        )
+    return config