feat(tasks): full REST surface for tasks

CRUD, lifecycle transitions, work-graph links and notes over /tasks;
share link-kind inference (TaskTargetKinds) between the REST route and
task_update tool. End-to-end route tests.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/tasks/src/main/kotlin/com/correx/core/tasks/TaskTargetKinds.kt

@@ -0,0 +1,16 @@
+package com.correx.core.tasks
+
+import com.correx.core.events.types.TaskTargetKind
+
+/**
+ * Infers what a work-graph link points at from its target id, for callers that don't say
+ * explicitly. ADR ids (`adr-12`, `ADR_0007`) and `.md` paths are documents; everything else is
+ * assumed to be another task. Shared by the agent tool and the REST surface so the heuristic
+ * stays in one place. Always prefer an explicit [TaskTargetKind] when the caller provides one.
+ */
+object TaskTargetKinds {
+    private val ADR_ID = Regex("(?i)^adr[-_ ]?\\d+$")
+
+    fun infer(targetId: String): TaskTargetKind =
+        if (ADR_ID.matches(targetId) || targetId.endsWith(".md")) TaskTargetKind.DOC else TaskTargetKind.TASK
+}