chore(community): rewards program, issue templates, and triage workflow (#176)

* chore(community): rewards program, issue templates, and triage workflow

Adds the public-facing community engagement infrastructure.

CONTRIBUTING.md introduces a three-tier rewards program (sticker / t-shirt /
hoodie) gated on merged PRs, with explicit eligibility rules to keep the
program sustainable. Fulfillment is handled by emailing support@kaelio.com.

The .github/ISSUE_TEMPLATE/ forms give structure to bug reports and feature
requests, and config.yml routes questions to the KTX Slack instead of GitHub
Discussions (matching the routing established in docs-site/.../support.mdx).

The triage-issues workflow applies a needs-triage label only when the issue
author isn't OWNER, MEMBER, or COLLABORATOR — so internal issues stay clean
while external contributions get queued for maintainer review.

The first 14 connector contribution issues (#161-174) have been filed using
these labels and reward tiers.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* chore(community): add SECURITY.md

Documents the private reporting channel (GitHub Security Advisories with
support@kaelio.com as fallback), what reporters should include, and the
supported-version policy.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,39 @@
+name: Feature request
+description: Propose a new feature or improvement
+title: "[feature] "
+labels: ["enhancement"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        For bug reports, use the bug template. For questions, use the
+        [KTX Slack](https://join.slack.com/t/ktxcommunity/shared_invite/zt-3y9b44m1x-LVyNNJD5nwaZHq4XS29LMQ).
+  - type: textarea
+    id: request
+    attributes:
+      label: What do you want, and why?
+      description: Describe the problem and your proposed solution.
+    validations:
+      required: true
+  - type: dropdown
+    id: area
+    attributes:
+      label: Which area?
+      options:
+        - CLI / setup
+        - Connectors
+        - Context engine
+        - Python semantic layer
+        - Python daemon
+        - Docs
+        - Other
+    validations:
+      required: true
+  - type: checkboxes
+    id: contribute
+    attributes:
+      label: Want to contribute this?
+      options:
+        - label: Yes, I'd like to open a PR
+        - label: I'd like guidance, then I'll open a PR
+        - label: No, just reporting the idea