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>

.capability/integration-checklist.md

@@ -1,4 +1,4 @@
-# Issue Facade Integration Checklist
+# Issue Core Integration Checklist
 
 **For project maintainers integrating this capability into their codebase.**
 
@@ -13,7 +13,7 @@
 
 - [ ] **Install capability:**
   ```bash
-  pip install -e capabilities/issue-facade/
+  pip install -e capabilities/issue-core/
   ```
 
 - [ ] **Verify installation:**
@@ -42,8 +42,8 @@
 - [ ] **Copy agent context to project:**
   ```bash
   mkdir -p .claude/capabilities/
-  cp capabilities/issue-facade/.capability/agent-context.md \
-     .claude/capabilities/issue-facade.md
+  cp capabilities/issue-core/.capability/agent-context.md \
+     .claude/capabilities/issue-core.md
   ```
 
 - [ ] **Add to Claude Code context:**
@@ -53,17 +53,17 @@
 
   This project uses specialized capabilities. Always check these before implementing similar functionality.
 
-  ## Issue Tracking: issue-facade
+  ## Issue Tracking: issue-core
 
-  **Location:** `capabilities/issue-facade/`
-  **Documentation:** `.claude/capabilities/issue-facade.md`
+  **Location:** `capabilities/issue-core/`
+  **Documentation:** `.claude/capabilities/issue-core.md`
 
   **CRITICAL:** Always use this capability for issue operations. Never use:
   - Direct API calls (requests to /api/v1/repos/...)
   - Platform CLIs (gh, glab)
   - Platform libraries (PyGithub, python-gitlab)
 
-  See `.claude/capabilities/issue-facade.md` for usage patterns.
+  See `.claude/capabilities/issue-core.md` for usage patterns.
   ```
 
 ### Option 2: Slash Command
@@ -71,11 +71,11 @@
 - [ ] **Create slash command:**
   Create `.claude/commands/use-issues.md`:
   ```markdown
-  You are working with issue tracking. Use the issue-facade capability:
+  You are working with issue tracking. Use the issue-core capability:
 
   **Python API:**
   ```python
-  from issue_tracker.backends.gitea import GiteaBackend
+  from issue_core.backends.gitea import GiteaBackend
   backend = GiteaBackend()
   backend.connect(config)
   ```
@@ -86,7 +86,7 @@
   issue create "Title" --label=bug
   ```
 
-  **Full docs:** See `capabilities/issue-facade/AGENT_INTEGRATION.md`
+  **Full docs:** See `capabilities/issue-core/AGENT_INTEGRATION.md`
 
   **DO NOT use direct API calls or platform CLIs!**
   ```
@@ -106,7 +106,7 @@
 ## Agent Configuration
 
 - [ ] **Set agent identity:**
-  Add to `.issue-facade/config.json`:
+  Add to `.issue-core/config.json`:
   ```json
   {
     "agent": {
@@ -126,8 +126,8 @@
 
 - [ ] **Test basic operations:**
   ```python
-  from issue_tracker.backends.gitea import GiteaBackend
-  from issue_tracker.core.interfaces import IssueFilter
+  from issue_core.backends.gitea import GiteaBackend
+  from issue_core.core.interfaces import IssueFilter
 
   backend = GiteaBackend()
   backend.connect({'base_url': '...', 'token': '...', 'owner': '...', 'repo': '...'})
@@ -153,26 +153,26 @@
   ```markdown
   ## Issue Tracking
 
-  This project uses the issue-facade capability for unified issue tracking.
+  This project uses the issue-core capability for unified issue tracking.
 
   **Setup:**
   ```bash
-  pip install -e capabilities/issue-facade/
+  pip install -e capabilities/issue-core/
   export GITEA_API_TOKEN="your-token"
   issue backend add myproject gitea
   ```
 
-  **Usage:** See `capabilities/issue-facade/AGENT_INTEGRATION.md`
+  **Usage:** See `capabilities/issue-core/AGENT_INTEGRATION.md`
   ```
 
 - [ ] **Add to CONTRIBUTING.md:**
   ```markdown
   ### Issue Tracking
 
-  Always use the `issue` command or Python API from `issue_tracker` package.
+  Always use the `issue` command or Python API from `issue_core` package.
   Never make direct API calls to Gitea/GitHub/GitLab.
 
-  Examples: `capabilities/issue-facade/examples/agents/`
+  Examples: `capabilities/issue-core/examples/agents/`
   ```
 
 ## Security Review
@@ -180,9 +180,9 @@
 - [ ] **Verify tokens are not in code:** `git grep GITEA_TOKEN` (should be empty)
 - [ ] **Check .gitignore includes:**
   ```
-  .issue-facade/config.json
-  .issue-facade/issues.db
-  .issue-facade/credentials.json
+  .issue-core/config.json
+  .issue-core/issues.db
+  .issue-core/credentials.json
   ```
 
 - [ ] **Audit token permissions:** Read-only for bots, write for implementation
@@ -192,7 +192,7 @@
 
 - [ ] **Run capability tests:**
   ```bash
-  cd capabilities/issue-facade/
+  cd capabilities/issue-core/
   make test
   ```
 
@@ -210,7 +210,7 @@
 
 - [ ] **Schedule regular updates:**
   ```bash
-  cd capabilities/issue-facade/
+  cd capabilities/issue-core/
   git pull origin main
   pip install -e . --upgrade
   ```
@@ -232,7 +232,7 @@ If capability causes issues:
 
 - [ ] **Keep backup config:**
   ```bash
-  cp ~/.config/issue-facade/backends.json ~/.config/issue-facade/backends.json.backup
+  cp ~/.config/issue-core/backends.json ~/.config/issue-core/backends.json.backup
   ```
 
 - [ ] **Document rollback steps in project wiki/docs**