feat: rename to issue-core and add task ingestion endpoint

Renames the package, distribution, CLI alias, Makefile targets, and
working directory from issue-facade to issue-core, signalling its
role as the authoritative task lifecycle manager for the Coulomb org
(peer to activity-core, rules-core, project-core).

Adds POST /issues/ ingestion endpoint for activity-core's IssueSink,
under a new optional [api] extra. The endpoint is served by `issue
serve`, authenticates via the ISSUE_CORE_API_KEY env var (Bearer or
X-API-Key header), and routes the TaskSpec payload to the configured
default backend with full traceability metadata embedded in
sync_metadata.

- T01: Python package issue_tracker -> issue_core, dir rename
- T02: registered in state hub under custodian domain
- T03: INTENT.md (what it is, what it isn't, how it fits)
- T04: SCOPE.md (in/out-of-scope, integration boundaries)
- T05: POST /issues/ via FastAPI + Uvicorn, 9 unit tests
- T06: docs/nats-task-ingestion.md design stub

Closes ISSC-WP-0001.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

issue_core/__init__.py

@@ -1,24 +1,24 @@
-"""
-Universal Issue Tracking System
-
-A backend-agnostic issue tracking system that supports multiple backends
-through a plugin architecture. Designed to be extracted into a standalone
-repository for use across multiple projects.
-
-Features:
-- Unified issue model across all backends
-- Plugin-based backend architecture
-- Local SQLite backend for offline work
-- Bidirectional synchronization
-- CLI-first interface
-- Support for GitHub-style and other issue tracking systems
-
-Supported Backends:
-- Local SQLite (for offline/standalone use)
-- Gitea (GitHub-compatible API)
-- Future: GitHub, GitLab, JIRA, Redmine, etc.
-"""
-
-__version__ = "0.1.0"
-__author__ = "MarkiTect Project"
-__description__ = "Universal Issue Tracking System with Plugin Architecture"
+"""
+issue-core — Authoritative Task Lifecycle Manager
+
+The single observable place in the Coulomb org where tasks land —
+regardless of whether they were created by a human, by activity-core,
+or by an agent. Backend-agnostic via a plugin architecture.
+
+Features:
+- Unified issue model across all backends
+- Plugin-based backend architecture
+- Local SQLite backend for offline work
+- Bidirectional synchronization
+- CLI-first interface
+- REST ingestion endpoint for activity-core's IssueSink
+
+Supported Backends:
+- Local SQLite (offline/standalone)
+- Gitea (GitHub-compatible API)
+- Future: GitHub, GitLab, JIRA, Redmine
+"""
+
+__version__ = "0.2.0"
+__author__ = "Coulomb / MarkiTect Project"
+__description__ = "Authoritative task lifecycle manager with plugin architecture"