fix(init): refuse to index the filesystem root or $HOME

[vitaliyslion]

Summary

gortex init had no guard against being pointed at a dangerous root — running it against $HOME (or /) walks the entire tree by default, since --skills defaults to on. gortex track already refused these paths via indexer.UnsafeIndexRootReason; init never called it. This wires the same guard into init, checked before the wizard, any indexing, or any file writes.

Changes

• cmd/gortex/init.go: runInit now resolves absRoot immediately after parsing the [path] arg and, unless --force is set, calls indexer.UnsafeIndexRootReason(absRoot) before doing anything else (wizard, indexing, or writes). Refuses with the reason plus ; pass --force to init it anyway when the target is the filesystem root, a Windows drive root, or exactly $HOME. Removed the now-redundant later filepath.Abs(root) recomputation. Updated the --force flag help text to mention the new bypass.
• cmd/gortex/init_integration_test.go: added TestInitRefusesHomeDirectory (asserts the refusal, its error message, and that no .gortex/ marker is written) and TestInitForceBypassesHomeDirectoryGuard (asserts --force still proceeds).

Testing

• New tests added for new functionality (TestInitRefusesHomeDirectory, TestInitForceBypassesHomeDirectoryGuard)
• go test ./cmd/gortex/... -run TestInit — all init/init-wizard tests pass
• go build ./cmd/gortex/...
• Manually verified with a built binary: gortex init "$HOME" --yes refuses with the home-directory message; gortex init "$HOME" --yes --force proceeds
• Full go test -race ./... not run (scoped to the touched package; happy to run the full suite before merge if wanted)
• Benchmarks — not performance-relevant

Checklist

• Code follows existing patterns in the codebase (mirrors the unsafeRootBlocked/pass force to track it anyway convention already used by gortex track)
• No unnecessary abstractions added
• Language extractor includes Meta["methods"] for interfaces (not applicable)
• Methods have EdgeMemberOf edges to their containing type (not applicable)

[zzet]

@vitaliyslion can you please check the failed test?

UPD: Looks like a flaky test