tui: migrate off deprecated Bubble Tea mouse Type API (SA1019)

[gnanam1990]

Summary

Clears the 11 SA1019 deprecation findings in internal/tui (surfaced by the v16 audit) by migrating the mouse helpers off the deprecated msg.Type / tea.MouseLeft|MouseMotion|MouseRelease|MouseWheelUp|MouseWheelDown API to the current Button/Action pair.

Why it's safe (no behavior change)

Bubble Tea's mouse parser always sets Button+Action as the source of truth and merely derives the deprecated Type field from them (parseMouseButton's "backward compatibility" switch). So the || msg.Type == … fallbacks in the five helpers were pure redundancy. In particular a left-button drag is reported as Action==Motion (with Type derived to MouseLeft), which mouseMotion already matches via Action==Motion — so dropping Type changes nothing.

• 5 helpers (mouseLeftPress, mouseMotion, mouseRelease, mouseWheelUp, mouseWheelDown) now use Button/Action only.
• The left-drag test drops the deprecated Type: field and asserts the Action==Motion path directly (its 1 SA1019 too).

Verification

staticcheck ./internal/tui/ SA1019 count: 11 → 0. Existing mouse + transcript-selection tests pass under -race. gofmt · vet · build (host + linux + windows) · full go test ./... · deadcode (no new vs main) all green.

First of the audit-hygiene / remaining-backlog items.

Summary by CodeRabbit

• Refactor
  • Removed deprecated event classification fallback logic, streamlining to use only current event fields.
  • Updated corresponding tests to reflect the updated behavior.

[github-actions]

Zero automated PR review

Verdict: No blockers found

Blockers

• None found.

Validation

• [pass] Diff hygiene: git diff --check
• [pass] Tests: go test ./...
• [pass] Build: go run ./cmd/zero-release build
• [pass] Smoke build: go run ./cmd/zero-release smoke

Scope

Head: 8b7b8296acc2
Changed files (2): internal/tui/mouse.go, internal/tui/mouse_test.go

This deterministic review checks validation status and basic diff hygiene. A human reviewer still owns product judgment and design quality.

[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between f857c4a and 8b7b829.

📒 Files selected for processing (2)

• internal/tui/mouse.go
• internal/tui/mouse_test.go

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Walkthrough

Mouse event classification helpers (mouseLeftPress, mouseMotion, mouseRelease, mouseWheelUp, mouseWheelDown) are updated to check only tea.MouseMsg.Button and Action fields, removing all legacy msg.Type fallback branches. A comment is added explaining the removal. The corresponding drag-motion test drops the Type field from its MouseMsg construction.

Changes

Remove deprecated msg.Type fallback from mouse event helpers

Layer / File(s)	Summary
Drop msg.Type branches and align test internal/tui/mouse.go, internal/tui/mouse_test.go	Five mouse classification helpers now check only Button+Action; a comment explains the removed Type fallback. The left-drag test constructs MouseMsg with Button: MouseButtonLeft + Action: MouseActionMotion and no Type field.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 16.67% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: migrating away from deprecated Bubble Tea mouse Type API while addressing SA1019 lint findings.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/tui-mouse-api

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[gnanam1990]

Consolidating the audit-backlog work into a single PR with one commit per change (per request). This change is preserved verbatim as a commit there.