v0.5.2 — lyrics-pane fill + per-row pause + click-to-preview when idle

✅ v0.5.2 — UX fix-pass: lyrics-pane fill + row-button play/pause toggle (2026-04-30)

User-reported UX gaps spotted on the v0.5.1 build:

1. Lyrics pane was small. LyricsPanel called setFixedHeight(150) and NowPlayingPane finished its QVBoxLayout with addStretch(1) after the panel — together those two pinned the lyrics block to ~150 px and let empty space accumulate underneath. On a tall window the lyrics area looked stranded in the upper third of the right pane.
2. Per-row ▶ button was load-only. Clicking the row's preview-play button on the currently-playing row reloaded the source from scratch (set_source + play), instead of toggling pause as the transport bar's main play/pause button does. The transport's play/pause button worked correctly — only the per-row button lacked the toggle.

Spec amendments (signed off via 2-pass cold-eyes review, 7 → 0 findings):

• Spec 06 §user-visible-behavior — per-row preview-play button is now a load-or-toggle control with explicit four-state glyph mapping (PLAYING-on-active-source → Glyphs.PAUSE; PAUSED / STOPPED / ERROR / non-active → Glyphs.PLAY). Adds an ERROR-state same-row-click bullet (re-runs set_source + play()) and an Errors-table row for "active source's file removed between load and a same-row click."
• Spec 06 test contract — TC-06-15 amended to flag that it supersedes the v0.4.0 signal-only assertion in test_library_pane_emits_preview_play_request; new TC-06-17 (active+playing → pause without reload), TC-06-18 (active+paused → resume), TC-06-19 (per-row glyph mapping with library-pane vs album-order-pane a11y bifurcation + dataChanged-row-range observable for the perf claim).
• Spec 07 §Lyrics panel — panel now fills the available right-pane height below now-playing metadata, with a 150 px minimum (the pre-amendment fixed value) enforced via setMinimumHeight instead of setFixedHeight. New TC-07-16 with a measurable qtbot assertion (resize(420, 800) → lyrics_panel.height() >= 300).

Shipped:

• ✅ Step 3 — failing tests for TC-06-17/18/19 + TC-07-16 (10 of 11 red on the implementation-side, 1 already passing as the existing cross-row case).
• ✅ Step 4 — implementation (lifted setFixedHeight(150) → setMinimumHeight(150), dropped competing addStretch after the lyrics panel, added LibraryPane.set_active_play_state + AlbumOrderPane.set_active_play_state, routed Player.state_changed + source-swap into both panes from MainWindow, added load-or-toggle dispatch in _on_preview_play).
• ✅ Step 5/6 — /audit + /indie-review in parallel (1 audit + 5 review findings, all L). Round 1 folded inline: pyright None-guard on album_order_pane.py:173, spec-06 PAUSED-vs-STOPPED split (PAUSED→toggle, STOPPED→fresh-load+restart), TC-06-15 marker disambiguation on the v0.4.0 test, and 2 new TC-06-19 tests for the album-order pane (set_album re-render preservation + set_active call-count observable). Round 2 convergence confirmed clean.
• ✅ Step 8/9 — flipped status to ✅; commit pending; push pending user OK.

Convergence trace: spec amendments 1-pass cold-eyes review (7 → 0 findings), implementation, post-implementation /audit + /indie-review (6 → 0 findings). 471 → 484 passing tests (+13: 11 new TC-06-17/18/19 + TC-07-16 contracts and 2 round-1-fold-out additions). Ruff clean. Manual smoke-launch on the Tracks/ corpus completed without error.

v0.5.2 follow-up — click-to-preview-when-idle (2026-04-30)

Same release wave; user feedback after the v0.5.2 commit: the running ~/.local-installed app was still v0.4.1 (the install.sh deploy hadn't been re-run after the v0.5.2 source-tree commit), so the lyrics-pane fill + per-row pause weren't observed. Triaged that as a deployment gap (re-run install.sh). Same round, the user requested a new behaviour: clicking a track row (anywhere outside the play / toggle column) should populate the now-playing pane with that track's metadata + lyrics, but only when nothing is playing.

Spec amendments (signed off via 1-pass cold-eyes review, 10 → 0 findings):

• Spec 06 §user-visible-behavior — new top bullet "Row body click previews-without-playing when idle" with sub-bullets for: hit-zones (library = non-_play / non-_toggle columns; album-order = label area only, drag-handle and play button excluded), keyboard-navigation parity (preview is mouse-click only — Enter routes through a separate _on_table_activated slot that handles only _play/_toggle), app-start state (STOPPED on launch, preview enabled from first click; restored last_played_track_path is not mutated by preview), Player.source() decoupling during preview, hover affordance (PointingHand cursor when STOPPED, Arrow otherwise — applies to both panes' viewports).
• Spec 06 Errors table — new row for "late state_changed(STOPPED) arrives after preview populated the now-playing pane" (preview metadata wins; state_changed only repaints row glyphs, not the now-playing block).
• Spec 06 test contract — TC-06-20 (STOPPED → preview), TC-06-21 (PLAYING/PAUSED/ERROR → no-op), TC-06-22 (album-order pane parity), TC-06-23 (last_played_track_path not mutated), TC-06-24 (late STOPPED clobber), TC-06-25 (keyboard nav inert), TC-06-26 (cursor mapping for all four states).

Code changes:

• LibraryPane — new row_body_clicked signal; _on_table_clicked emits it for non-_play/_toggle columns; new _on_table_activated slot handles keyboard activation (no row-body branch); new set_row_body_cursor_for_state(stopped=) method.
• _OrderRowWidget — new body_clicked signal; overridden mousePressEvent captures press position; overridden mouseReleaseEvent emits body_clicked only when the press → release delta is within QApplication.startDragDistance() (so genuine drags don't fire previews); label has WA_TransparentForMouseEvents so clicks fall through to the row widget.
• AlbumOrderPane — new row_body_clicked signal; set_album connects each row's body_clicked to re-emit the row's path; new set_row_body_cursor_for_state(stopped=) mirroring the library pane.
• MainWindow — new _on_row_body_clicked(path) handler gates on Player.state() == STOPPED, then set_track + _sync_lyrics_for_track; missing-track shows toast (mirroring _on_preview_play); _on_player_state_changed_for_rows flips both panes' cursors and is now also called once at end of __init__ so the construction-time cursor is correct without waiting for a state-change emission.

Audit/review trace: post-implementation /audit + /indie-review (12 → 0 findings, all H+M folded inline). 484 → 500 passing tests (+16: 9 initial TC-06-20..26 contracts + 7 round-1-fold-out additions covering ERROR-state no-op, PAUSED+ERROR cursor, real-mousePress plumbing, play-button-negative case, fresh-LRC lyrics population, Enter-doesn't-preview, construction-time cursor). Ruff clean. Manual smoke pending on ~/.local install (gated on the running v0.4.1 instance being closed first).

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