feat(tools): 5 more native perf tools — sort, head_tail, base64, tr, word_count

sort — Sort lines in one or more files natively. Supports asc/desc,
  unique, numeric, case-insensitive, reverse. Replaces sort fork.

head_tail — Read first/last N lines of files (streaming, parallel).
  head: stops after N lines (no full-file read). tail: ring buffer.
  Replaces head -n, tail -n forks.

base64 — Encode/decode base64 for files or inline strings. Uses Go
  encoding/base64 stdlib. Replaces base64 fork.

tr — Native text transformation: case conversion (upper/lower),
  string substitution, character replacement, character deletion.
  Chainable transformations applied in order. Replaces tr, sed forks.

word_count — Streaming word counter (words, lines, chars, bytes) for
  up to 20 files in parallel. Replaces full wc fork.

Security: all gated through danger.ClassifyPath + CheckOperation,
  O_NOFOLLOW on file opens, registered in classifyToolCall() for
  batch approval gate. 17 new tests. 0 new dependencies.

Author: molty3000

cmd/odek/main.go

@@ -1410,6 +1410,11 @@ func builtinTools(dc danger.DangerousConfig, sm *skills.SkillManager, approver d
 		&jsonQueryTool{dangerousConfig: dc},
 		&treeTool{dangerousConfig: dc},
 		&checksumTool{dangerousConfig: dc},
+		&sortTool{dangerousConfig: dc},
+		&headTailTool{dangerousConfig: dc},
+		&base64Tool{dangerousConfig: dc},
+		&trTool{dangerousConfig: dc},
+		&wordCountTool{dangerousConfig: dc},
 		newBrowserTool(dc),
 	}