Render one symbol per Claude pane within each tab

[anateus]

Summary

Tabs with multiple Claude panes used to flicker between activity states because the renderer picked one "best" session per tab. Each pane now gets its own symbol slot.

Per-pane symbols

• One symbol per Claude pane, ordered stably by pane_id so the layout doesn't reshuffle as activity changes.
• Each symbol is rendered in a fixed 2-col cell so wide glyphs (⚡ ⚙ ▶ ⚠) and narrow glyphs no longer cause tab width to flicker as activity transitions.
• Each symbol is its own click target that focuses that pane; the tab name still switches tabs. Waiting flashes are scoped to the affected symbol instead of pulsing the whole tab.
• Adaptive name length: budget = (cols − fixed) / count, capped at 20. Names truncate when tight, drop when very tight; symbols stay visible.

Settings

• Drops the elapsed_time setting (ambiguous which pane it'd refer to with multi-pane). Existing configs with the field still parse — serde ignores unknown keys.

Reliability fixes (review feedback)

• render_tabs overflow guard now uses the actual per-tab fixed width and reserves the closing-arrow column. Wide tabs can no longer overflow into the next tab or register click regions for off-screen cells.
• merge_sessions compares last_ts_ms when either side has it, falling back to last_event_ts only for old payloads. Per-pane rendering made same-second drops user-visible.
• Symbol click regions are tight to the symbol cell — separator gaps no longer focus the previous pane.

Plumbing

• ClickRegion refactored from (tab_index, pane_id, is_waiting) to a ClickAction { FocusPane | SwitchTab } enum.
• README updated to describe per-pane symbols and per-symbol click semantics; replaces stale "elapsed time" row with the existing "mode indicator" toggle.
• Version bumped to 0.5.1.

Test plan

• Builds clean for wasm32-wasip1 (release + clippy)
• Loaded into a live Zellij session with multiple Claude panes per tab; symbols render per pane in stable order, no flicker
• Tab width is stable as Bash (⚡, wide) starts and stops
• Verify per-symbol flash pulses only the waiting pane's symbol on a tab with several active Claude panes
• Verify clicking the warning symbol focuses the waiting pane
• Verify clicking the tab name switches tabs
• Verify name adapts (truncates / drops) on a narrow terminal

[anateus]

With multiple panes displaying all the elapsed times is a bit cumbersome so I decided to drop it, but obviously that's easy to adjust/revert. Just wanted to mention that it was intentional :)

[ishefi]

Thanks for this, it's the more complete take. Fixed-width symbol cells, per-symbol click regions via the new ClickAction enum, scoped flash, and the merge_sessions last_ts_ms fix all land cleanly together. Two things before merge:

1. Ordering. Sorting by pane_id is stable but doesn't match what the user sees in the tab. PR feat: render multiple status icons per one tab #9 sorts by pane geometry (pane_y, pane_x) from pane_manifest, filtering is_plugin panes. Could you adopt that? pane_id ordering is arbitrary from the user's POV; geometry is what they expect.
2. Dropping elapsed_time. I get the ambiguity argument, but PR feat: render multiple status icons per one tab #9 keeps it for the single-session case, which is still useful for spotting stuck sessions. Worth preserving with sessions.len() == 1 rather than removing the setting outright.

Otherwise lgtm. The README + version bump + addressed review feedback make this the cleaner base to land.