chore: negation patterns for force-tracked files under ignored specs/ dir

[satwareAG-ironMike]

Problem

git add on the force-tracked IPADP meta files under specs/ exits nonzero with the "paths are ignored" advice even though staging succeeds. This silently breaks git add ... && git commit chains (hit twice during the v1.0.4 sync, 2026-09-03).

Root cause

.gitignore line 62 ignores specs/ wholesale (upstream dogfooding rule). Three meta files are force-tracked under it:

• specs/metadata.json
• specs/upstream-release-sync-strategy/spec.md
• specs/upstream-release-sync-strategy/checklists/requirements.md

Git cannot re-include files inside an excluded directory, so plain !specs/... negations do not work; the rule must become specs/* plus child negations.

Acceptance criteria

• git add specs/metadata.json exits 0 (no advice message)
• Untracked dogfooding content under specs/ still ignored (e.g. a scratch specs/foo/ dir never shows in git status)
• Upstream's ignore intent preserved; fork additions clearly marked and appended at EOF (minimal merge-conflict surface)