fix(#37): expand ~ in dataset path (interactive prompt + literal arg)

[aptracebloc]

Closes #37.

~ is expanded by the shell, not by programs — so dataset push ~/data works (the shell rewrites ~→$HOME before the CLI starts), but a ~/data typed at the interactive prompt (#28) reaches the CLI literally, and filepath.Abs then prepends the CWD:

Error: reading dataset directory "/Users/arturo/work/cli/~/tb-fixtures/tab-reg": … no such file or directory

Fix

• New expandHome(path) (mirrors cluster.expandPath): a leading ~ / ~/… → $HOME; relative, absolute, and empty paths untouched.
• Applied in runDatasetPush right after a.LocalPath is resolved — before any push.Discover* call — so it covers both the interactive prompt and a quoted/literal ~ positional arg (e.g. in a --no-input script) in one place.

Acceptance criteria

• ~/x and ~ resolve under $HOME; relative (./x) and absolute paths unchanged.
• Works for both the interactive prompt and a literal ~ arg (same code path).
• Unit test (TestExpandHome): ~, ~/x, ~/a/b, ./x, /abs, relative, empty.
• (Optional) in-prompt existence validator — deferred: it would couple the hermetic prompt-mapping unit tests to real directories on disk. Easy follow-up if wanted.
• make ci green.

Verification

Live, with a quoted '~/tb-fixtures/tab-reg' (the shell can't expand it — the exact bug condition) on EKS dev:

  destination:   /data/shared/demo_tilde
Dry-run complete — no cluster resources were created.

Pre-fix this died at the directory read; now it resolves under $HOME and runs through.

🤖 Generated with Claude Code

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Note

Low Risk
Small, localized path normalization before local file discovery; behavior change only for paths that start with ~.

Overview
Fixes #37 by expanding a leading ~ / ~/… on the dataset local path inside dataset push, so paths from the interactive prompt or quoted CLI args resolve under $HOME instead of being treated as relative to the CWD.

Adds expandHome in internal/cli/dataset.go (same behavior as cluster.expandPath for kubeconfig) and runs it on a.LocalPath in runDatasetPush immediately after the path is known and before any push.Discover* walk. Relative, absolute, and empty paths are unchanged; if $HOME cannot be resolved, the literal path is kept for clearer downstream errors.

Adds TestExpandHome in coverage_test.go covering ~, ~/…, and pass-through cases.

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[LukasWodka]

👋 Heads-up — Code review queue is at 15 / 8

Above the WIP limit. The team convention is to review existing PRs before opening new work.

Open PRs currently in Code review (oldest first):

• averaging-service#102 — chore(kanban): declare staging as prod-truth branch via .kanban.yml · author: @LukasWodka · no reviewer assigned
• averaging-service#98 — ci: add fr-gate caller workflow · author: @LukasWodka · no reviewer assigned
• client#191 — fix(#190): fail image-refresh loudly when the ingestor (ghcr) digest can't resolve · author: @saadqbal · no reviewer assigned
• client#192 — Installer UX: drop PriorityClass, fix namespace, one-per-machine guard, surface version · author: @LukasWodka · no reviewer assigned
• client#194 — test(requests-proxy): add helm-unittest coverage for requests-proxy Deployment · author: @saadqbal · no reviewer assigned
• client-runtime#63 — feat(docs: sync v0.3.0 README to main #59): single-writer PodTokenReconciler + RECONCILER_MODE wiring + deploy-window lock · author: @saadqbal · no reviewer assigned
• data-ingestors#146 — test(schema): lock category enum to the engine's TaskCategory (anti-drift) · author: @LukasWodka · reviewer: @saadqbal
• data-ingestors#148 — Develop to prod · author: @divyasinghds · reviewer: @saadqbal
• design-system#19 — fix: un-track coverage/ and node_modules/ from git · author: @LukasWodka · no reviewer assigned
• design-system#22 — ci: add Vitest test workflow · author: @LukasWodka · reviewer: @aptracebloc

Pull from review before opening new work. (This is a nudge from the kanban WIP check, not a block.)