feat: initial blink-cmp-ssh implementation

Problem: the existing blink-cmp-sshconfig plugin uses a synchronous,
build-time Python scraping approach that requires uv and make to
generate a static Lua file.

Solution: implement a runtime, async blink.cmp source that parses
ssh_config keywords from man ssh_config and enum values from ssh -Q
queries, matching the architecture of blink-cmp-tmux and
blink-cmp-ghostty.

.busted

@@ -0,0 +1,9 @@
+return {
+  _all = {
+    lua = 'nvim -l',
+    ROOT = { './spec/' },
+  },
+  default = {
+    verbose = true,
+  },
+}