LSP: `debian/rules` should flag hook targets that conflicts with the debputy integration level

If you have migrated (partially) to debputy, it would make sense for debputy to flag problematic hook targets that conflicts with the debputy integration.

• Flag hooks when sequence is activated via Build-Depends
• Flag hooks when sequence is activated via dh ... --with foo
• Changes to the sequences do not seem to trigger immediately (update d/control should trigger a re-check of debian/rules, but it does not).
  • Note: This cannot be fully solved until https://github.com/microsoft/language-server-protocol/issues/1964 / https://debbugs.gnu.org/cgi/bugreport.cgi?bug=72088 is fixed. But we can still improve it by listening for the save and then retrigger the diagnostic scan.
• Migrate to new dh_assistant feature instead of built-in to catch arbitrary commands not active in the sequence. Requires debhelper (>= 13.16~)
• Make the LSP version per debian directory rather than "global"