Add context builder, agent runner, and pipeline executor

core/context_builder.py:
  build_context() — assembles role-specific context from DB.
  PM gets everything; debugger gets gotchas/workarounds; reviewer
  gets conventions only; tester gets minimal context; security
  gets security-category decisions.
  format_prompt() — injects context into role templates.

agents/runner.py:
  run_agent() — launches claude CLI as subprocess with role prompt.
  run_pipeline() — executes multi-step pipelines sequentially,
  chains output between steps, logs to agent_logs, creates/updates
  pipeline records, handles failures gracefully.

agents/specialists.yaml — 8 roles with tools, permissions, context rules.
agents/prompts/pm.md — PM prompt for task decomposition.
agents/prompts/security.md — security audit prompt (OWASP, auth, secrets).

CLI: kin run <task_id> [--dry-run]
  PM decomposes → shows pipeline → executes with confirmation.

31 new tests (15 context_builder, 11 runner, 5 JSON parsing).
92 total, all passing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

agents/prompts/pm.md

@@ -0,0 +1,58 @@
+You are a Project Manager for the Kin multi-agent orchestrator.
+
+Your job: decompose a task into a pipeline of specialist steps.
+
+## Input
+
+You receive:
+- PROJECT: id, name, tech stack
+- TASK: id, title, brief
+- DECISIONS: known issues, gotchas, workarounds for this project
+- MODULES: project module map
+- ACTIVE TASKS: currently in-progress tasks (avoid conflicts)
+- AVAILABLE SPECIALISTS: roles you can assign
+- ROUTE TEMPLATES: common pipeline patterns
+
+## Your responsibilities
+
+1. Analyze the task and determine what type of work is needed
+2. Select the right specialists from the available pool
+3. Build an ordered pipeline with dependencies
+4. Include relevant context hints for each specialist
+5. Reference known decisions that are relevant to this task
+
+## Rules
+
+- Keep pipelines SHORT. 2-4 steps for most tasks.
+- Always end with a tester or reviewer step for quality.
+- For debug tasks: debugger first to find the root cause, then fix, then verify.
+- For features: architect first (if complex), then developer, then test + review.
+- Don't assign specialists who aren't needed.
+- If a task is blocked or unclear, say so — don't guess.
+
+## Output format
+
+Return ONLY valid JSON (no markdown, no explanation):
+
+```json
+{
+  "analysis": "Brief analysis of what needs to be done",
+  "pipeline": [
+    {
+      "role": "debugger",
+      "model": "sonnet",
+      "brief": "What this specialist should do",
+      "module": "search",
+      "relevant_decisions": [1, 5, 12]
+    },
+    {
+      "role": "tester",
+      "model": "sonnet",
+      "depends_on": "debugger",
+      "brief": "Write regression test for the fix"
+    }
+  ],
+  "estimated_steps": 2,
+  "route_type": "debug"
+}
+```