id(web): Find panel and Go to Line dialog never appear after the editor is recreated — module singletons outlive the editor, destroy helpers have no production caller #718

Problem

Find (Ctrl+F / Ctrl+H) and Go to Line (Ctrl+G) silently stop working after the editor is recreated — e.g. after disconnecting from one world/session and opening another file. The shortcuts return true but no panel/dialog ever appears in the new editor.

Root cause (same pattern, both modules)

Both modules keep their DOM in a module-level singleton that is created once for the first editor and never invalidated:

• pkgs/id/web/src/search-panel.ts: panelState (lines 47–54) is module-global. openPanel only creates the panel if (!panelState.panelEl), and panelState.view / the event handlers captured by setupPanelEvents are bound to the first view forever.
• pkgs/id/web/src/goto-line.ts: dialogEl / dialogInput (lines 14–16) are module-global. openGotoLine only creates the dialog if (!dialogEl). (It does refresh activeView, but the dialog element itself stays attached to the old container.)

Both modules export a destroy function (destroySearchPanel, destroyGotoLineDialog) documented as "Call this when the editor is being destroyed" — but nothing in production calls either one. The only callers are the test files' afterEach, which is why the existing suites never see the leak. Production teardown (pkgs/id/web/src/main.ts, disconnect path, ~line 1287) only calls this.collab.editor.view.destroy().

When the old container is removed from the document, the singleton element is detached with it. The next Ctrl+F / Ctrl+G "opens" the panel by setting style.display = "" on the detached node and focusing a detached input — invisible, and for search the handlers still dispatch to the destroyed first view.

Reproduction (verified this run, on main a8992eb)

A vitest case mirroring the production lifecycle — create editor 1, open the panel, view.destroy() + remove container (without calling the destroy helper, exactly as production does), create editor 2, trigger the shortcut — fails for both modules:

• search: second container has no .search-panel after Mod-f (expected null not to be null)
• goto-line: second container has no .goto-line-dialog after Mod-g (same)

Both pass if destroySearchPanel() / destroyGotoLineDialog() is called between editors, confirming the missing invalidation is the whole defect.

Acceptance criteria

• After an editor is destroyed and a new one created (no manual destroy-helper call in between), Ctrl+F/Ctrl+H shows a working find/replace panel in the new editor's container, bound to the new view (typing searches the new document; Enter/replace act on it).
• Same for Ctrl+G: the Go to Line dialog appears in the new container and jumps in the new document.
• Regression tests for both modules that recreate the editor without calling the destroy helpers (mirroring production teardown) and assert the panel/dialog appears and works in the second editor.
• Existing search-panel and goto-line suites still pass; typecheck clean.

Suggested fix shapes (either is fine): make openPanel/openGotoLine self-healing — if the singleton element is detached or belongs to a different container/view, destroy and recreate it bound to the current view — and/or call the destroy helpers from the editor teardown path in main.ts. The self-healing form is more robust: it also covers any future recreation path that forgets the teardown call.

Single-repo: no search-panel/goto-line copies exist in developing-today/opencode, developing-today/openchamber, or dezren39/nix (grep-verified this run).