feat: add !paste command and unit tests for 5 core plugins

Add cmd_paste to flaskpaste plugin (create paste, return URL).
Add test suites for encode, hash, defang, cidr, and dns plugins
(83 new test cases, 1093 total).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/USAGE.md

@@ -139,6 +139,7 @@ format = "text"               # Log format: "text" (default) or "json"
 | `!archive <url>` | Save URL to Wayback Machine |
 | `!resolve <host> [host2 ...] [type]` | Bulk DNS resolution via TCP/SOCKS5 |
 | `!shorten <url>` | Shorten a URL via FlaskPaste |
+| `!paste <text>` | Create a paste via FlaskPaste |
 | `!pastemoni <add\|del\|list\|check>` | Paste site keyword monitoring |
 
 ### Command Shorthand
@@ -902,6 +903,23 @@ https://paste.mymx.me/s/AbCdEfGh
 - mTLS client cert skips PoW; falls back to PoW challenge if no cert
 - Also used internally by `!alert` to shorten announcement URLs
 
+### `!paste` -- Create Paste
+
+Create a text paste via FlaskPaste.
+
+```
+!paste some text or data to paste
+```
+
+Output format:
+
+```
+https://paste.mymx.me/AbCdEfGh
+```
+
+- Pastes arbitrary text content
+- mTLS client cert skips PoW; falls back to PoW challenge if no cert
+
 ### `!pastemoni` -- Paste Site Keyword Monitor
 
 Monitor public paste sites for keywords (data leaks, credential dumps, brand