Fix: sending several selected headings drops the last heading's cards

[coralynnkc]

Problem

Reported against 1.01 and still present on main: select across several headings and press ` (Send to Speech) and the last heading doesn't come through properly. With H1, card1, H2, card2, H3, card3 selected from H1's text to H3's text:

• drag ends in H3's second half → sends H1, card1, H2, card2, H3 — H3 arrives bare, card3 left behind
• drag ends in H3's first half → sends H1, card1, H2, card2 — H3 missing entirely

Root cause: normalizeSelectionForSend rounds the selection end to the nearest top-level node boundary. Headings are flat siblings of their cards, not containers, so rounding to a heading's boundary never picks up its section. The bare-cursor path (enclosingStructureRange) already expands a heading to its section via sectionEndFromHeading; the selection path didn't.

Fix

In src/editor/send-normalize.ts:

• If the selection ends inside a heading with any of its text selected, that heading is included. A caret at its very start (e.g. after shift-down onto the next line) still leaves it out.
• If a heading ends the range, the range extends to the end of that heading's section (up to the next heading at the same or a higher level).
• The collapsed-selection fallback also expands a heading to its section, so selecting text inside one heading sends that section, same as a bare cursor.

The shared normalizer is used by takeSendSlice, so Send to Speech (at cursor / at end), Send to Starred / Recipient, and Send to Dropzone all get the fix. The widened range is also reflected back as the visible selection before sending.

Test plan

• New send-normalize cases: late end and early end in the last heading, stopping at the start of the next heading, the section stopping at a shallower heading, and a selection inside one heading's text
• Send-related suites pass (10 files, 106 tests)
• Manual: select H1 through H3's header text → ` → all three sections land in the speech doc

No changelog entry since there's no unreleased section yet; happy to add one wherever you'd like it.

https://claude.ai/code/session_01GX8wvCNHHvWsEyKwjqHPMo