feat: progress consolidation arc

[abiswas97]

Summary

Completes the progress consolidation arc across every producer and consumer.

• Replaces legacy/ad-hoc streams with an immutable progress.Plan, explicit execution lifecycle, execution-derived phases, completed-stream validation, sticky delivery errors, and auditable terminal reasons.
• Freezes integration, creator, repository, migration, and removal operations before execution. Stable semantic IDs keep totals deterministic across input reordering.
• Separates domain failures from infrastructure failures and propagates both consistently through CLI/TUI results.
• Preserves integration state transactionally: failed applies keep the previous selection and unrelated state.
• Pins the responsive live region across normal, compact, minimal, and emergency terminal heights; summaries and detail portals remain bounded, width-safe, live, and recoverable at 20 columns.
• Scopes motion to the focused running headline, honors SENTEI_MOTION=off and TERM=dumb, and installs hooks through the shared Git common directory.
• Adds deterministic, local-only VHS fixtures and tapes for before/after removal, successful removal, and dependent integration failure.

Safety and correctness

• Migration backups are atomically reserved at unique sibling paths, copied without shell interpolation, owned by the invocation, and removed only after owned failure cleanup.
• Integration index/teardown paths reject lexical and symlink escapes before inspection and are revalidated immediately before destructive copy/remove calls, including after integration commands.
• Removal keeps teardown command failures visible while declaring and attempting every artifact removal independently in deterministic order.
• The VHS fixture rejects symlinked, non-owned, or canonically mismatched roots and retained trees, including symlinks nested beneath outputs/ and frames/, before mutation.
• Preparing views, progress portals, summaries, and structured detail text fit emergency terminal sizes; open details refresh or close as progress state changes.

Verification

Fresh on head 06c9737:

go test -race ./...                    PASS
go vet ./...                           PASS
golangci-lint run ./...                0 issues
go build ./...                         PASS
git diff --check origin/main...HEAD    PASS

Additional evidence:

• bash -n, ShellCheck, fixture safety/idempotence tests, and all three vhs validate checks pass.
• All three GIFs rendered locally at 960x672 and were inspected at active, failure, and final frames; no clipping or row drift was found.
• Three independent final reviews covered correctness/safety, architecture/blast radius, and UX/accessibility. Every accepted Critical or Important finding was fixed test-first and re-reviewed as resolved.
• origin/main (4cfb16d) is an ancestor of this branch; no synchronization merge was required.

Generated GIF/PNG binaries remain local by design. Deterministic tape sources, fixture, safety tests, and README are included in the PR.

[codecov]

Codecov Report

❌ Patch coverage is 88.81965% with 305 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
internal/integration/apply.go	85.27%	36 Missing and 21 partials ⚠️
internal/creator/prepared.go	79.21%	19 Missing and 18 partials ⚠️
internal/progress/execution.go	90.94%	16 Missing and 10 partials ⚠️
internal/tui/confirm.go	84.35%	17 Missing and 6 partials ⚠️
internal/repo/migrate_prepared.go	88.06%	14 Missing and 7 partials ⚠️
internal/tui/help.go	82.75%	18 Missing and 2 partials ⚠️
internal/creator/preflight.go	81.55%	14 Missing and 5 partials ⚠️
internal/progress/validate.go	84.90%	10 Missing and 6 partials ⚠️
internal/tui/progress_layout.go	91.46%	7 Missing and 7 partials ⚠️
internal/repo/clone.go	91.95%	4 Missing and 3 partials ⚠️
... and 18 more

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