enhance: [skip e2e]add agentic bug report issue template (#47615)

## Summary
Add a new issue template (`agentic_bug_report.md`) optimized for AI
Agent to analyze, reproduce, and fix Milvus bugs autonomously.

### Why
The existing `bug_report.yaml` is designed for human users with
free-text fields. For an AI agent workflow (auto-analyze → locate code →
write fix → submit PR), we need more structured, machine-actionable
information.

### Template Structure
| Section | Purpose |
|---------|---------|
| **Environment** | Version (image tag / commit), deployment mode, SDK —
for agent to checkout matching code and set up environment |
| **Reproduction Script** | Self-contained, runnable Python/Go script
ending with assertion — agent can execute directly |
| **Reproduction Steps** | Alternative for systemic/stability/timing
issues that can't be scripted |
| **Trigger Conditions** | Frequency, timing, boundary conditions —
helps agent narrow down code paths |
| **Expected / Actual Behavior** | Structured comparison — defines
"fixed" criteria for agent verification |
| **Error Logs** | Key stack traces with file:line — agent can jump
directly to suspect code |
| **Non-default Configuration** | Config diff only — agent knows
defaults, only needs deltas |
| **Analysis Hints** | Optional clues: suspect code location, related
PRs, ruled-out directions |

### Design Principles
- Every field directly serves a step in the agent's workflow: understand
→ reproduce → locate → fix → verify
- Reproduction script is preferred (functional bugs) but structured
steps are accepted (stability/timing bugs)
- Minimal required fields to reduce filing friction while maximizing
agent effectiveness

🤖 Generated with [Claude Code](https://claude.ai/code)

Signed-off-by: yanliang567 <yanliang.qiao@zilliz.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/agentic_bug_report.md

@@ -0,0 +1,95 @@
+---
+name: "\U0001F916 Agentic Bug Report"
+about: Structured bug report optimized for AI Agent to analyze, reproduce, and fix autonomously
+title: "[Bug]: "
+labels: kind/bug, needs-triage
+assignees: yanliang567
+---
+
+## Environment
+
+- **Milvus Version**: <!-- image tag (e.g. master-20260204-e12a5b0b-amd64) or commit hash -->
+- **Deployment Mode**: <!-- standalone | cluster -->
+- **MQ**: <!-- rocksmq | pulsar | kafka -->
+- **SDK**: <!-- e.g. pymilvus v2.6.0 / go-sdk v2.6.0 -->
+- **OS**: <!-- e.g. Ubuntu 22.04 -->
+
+## Reproduction
+
+<!-- Provide ONE of the following: -->
+
+### Option A: Script (preferred for functional bugs)
+
+<!--
+Complete, runnable script that reproduces the bug.
+Requirements:
+- Must be self-contained (include collection creation, data insertion, index building, loading, etc.)
+- Must use a unique collection name to avoid conflicts
+- Connection defaults: host="localhost", port="19530"
+- End with an assertion or clear print that shows the bug
+-->
+
+```python
+
+```
+
+### Option B: Steps (for systemic / stability / timing issues)
+
+<!--
+Structured steps with specific parameters.
+Be precise: not "insert some data", but "10k rows/sec for 30 minutes".
+-->
+
+1. Deploy: <!-- deployment topology, e.g. 3 QueryNodes, 2 DataNodes -->
+2. Setup: <!-- collection schema, index params, load params -->
+3. Workload: <!-- exact operations, rate, duration -->
+4. Trigger: <!-- what operation or condition triggers the bug -->
+5. Observed via: <!-- metrics / logs / query result / crash -->
+
+### Trigger Conditions
+
+- **Frequency**: <!-- always | intermittent (~30%) | rare -->
+- **First observed after**: <!-- e.g. ~20 minutes of continuous load -->
+- **Does NOT happen when**: <!-- e.g. only 1 QueryNode / no compaction / default config -->
+
+## Expected Behavior
+
+<!-- What should happen. Be specific with numbers when possible. -->
+
+## Actual Behavior
+
+<!-- What actually happens. Be specific with numbers when possible. -->
+
+## Error Logs
+
+<!--
+Key error logs or stack traces. Only the relevant part, not full logs.
+If no error is raised (silent wrong result), state:
+"No error in logs, results are incorrect."
+-->
+
+```
+
+```
+
+## Non-default Configuration
+
+<!--
+Milvus server config that differs from default. Skip if all defaults.
+Only include relevant sections.
+-->
+
+```yaml
+
+```
+
+## Analysis Hints (Optional)
+
+<!--
+Any clues that help narrow down the root cause:
+- Suspect code location: e.g. internal/proxy/task_search.go
+- Related PR/commit: e.g. might be introduced by #12345
+- Trigger boundary: e.g. only happens with sealed segments, growing is fine
+- Already ruled out: e.g. not a SDK issue, confirmed by raw gRPC call
+- Related issues: e.g. #46820, #46972
+-->