Remove worktrees with initialized submodules by passing --force

[scgopi]

Problem

git worktree remove refuses worktrees whose submodules are initialized — fatal: working trees containing submodules cannot be moved or removed (reproduced on git 2.50.1; this repository's own ThirdParty/ghostty + zmx in a loop's worktree is the real-world case). Hygiene's removal passed --force only for dirty trees — and a submodule worktree reads clean (status --porcelain is empty) — so those worktrees were stuck: the sweeper offered them, git refused, the sheet named the refusal, nothing could go through.

Evidence

Setup	Result
initialized submodule, clean	plain remove → refused; single --force → removed, gitdir bookkeeping clean
.gitmodules present, submodule not initialized	plain remove → succeeds
uncommitted change inside a submodule	superproject porcelain shows M <sub> — already dirty by graphcode's read
dirty tree + initialized submodule	single --force → removed

So: the refusal is about initialized submodules only, one --force always suffices, and no deinit / rm -rf / double-force is ever needed.

Fix

• WorktreeGitFacts.hasSubmodules: initialized checkouts only. Local detection gates on .gitmodules (zero extra git calls for submodule-free repos) then reads git submodule status (a non-- line means populated); remote is one extra SSH round trip.
• Removal passes --force when submodules are present — without the discard confirmation: a pristine checkout is restorable from upstream, so the force is bookkeeping, not discard. Uncommitted work inside submodules keeps its protection via the superproject's dirty read (row 3 above).
• All three removal routes pass the flag: sweeper (fresh-inspection path, discardsFiles vs needsForce split), resolve moment (auto-remove), and card Reclaim — whose action now carries hasSubmodules, because the project scope clears the offer in the same action and the fact must survive it.

Tests

• WorktreeRemovalTests: clean submodule row is forced straight through, no confirmation raised.
• WorktreeHygieneTests: submodules change the removal mechanics, not the tier — still safe, still removable, removalDiscardsFiles stays false.
• 33/33 across WorktreeHygiene + WorktreeSweepFeature + WorktreeRemoval; swiftlint and swift-format clean.